1 /* If-conversion support.
2 Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005
3 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it
8 under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2, or (at your option)
12 GCC is distributed in the hope that it will be useful, but WITHOUT
13 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
14 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
15 License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING. If not, write to the Free
19 Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
24 #include "coretypes.h"
31 #include "insn-config.h"
34 #include "hard-reg-set.h"
35 #include "basic-block.h"
45 #include "tree-pass.h"
48 #ifndef HAVE_conditional_execution
49 #define HAVE_conditional_execution 0
51 #ifndef HAVE_conditional_move
52 #define HAVE_conditional_move 0
63 #ifndef HAVE_conditional_trap
64 #define HAVE_conditional_trap 0
67 #ifndef MAX_CONDITIONAL_EXECUTE
68 #define MAX_CONDITIONAL_EXECUTE (BRANCH_COST + 1)
71 #define NULL_BLOCK ((basic_block) NULL)
73 /* # of IF-THEN or IF-THEN-ELSE blocks we looked at */
74 static int num_possible_if_blocks
;
76 /* # of IF-THEN or IF-THEN-ELSE blocks were converted to conditional
78 static int num_updated_if_blocks
;
80 /* # of changes made which require life information to be updated. */
81 static int num_true_changes
;
83 /* Whether conditional execution changes were made. */
84 static int cond_exec_changed_p
;
86 /* True if life data ok at present. */
87 static bool life_data_ok
;
89 /* Forward references. */
90 static int count_bb_insns (basic_block
);
91 static bool cheap_bb_rtx_cost_p (basic_block
, int);
92 static rtx
first_active_insn (basic_block
);
93 static rtx
last_active_insn (basic_block
, int);
94 static basic_block
block_fallthru (basic_block
);
95 static int cond_exec_process_insns (ce_if_block_t
*, rtx
, rtx
, rtx
, rtx
, int);
96 static rtx
cond_exec_get_condition (rtx
);
97 static int cond_exec_process_if_block (ce_if_block_t
*, int);
98 static rtx
noce_get_condition (rtx
, rtx
*);
99 static int noce_operand_ok (rtx
);
100 static int noce_process_if_block (ce_if_block_t
*);
101 static int process_if_block (ce_if_block_t
*);
102 static void merge_if_block (ce_if_block_t
*);
103 static int find_cond_trap (basic_block
, edge
, edge
);
104 static basic_block
find_if_header (basic_block
, int);
105 static int block_jumps_and_fallthru_p (basic_block
, basic_block
);
106 static int find_if_block (ce_if_block_t
*);
107 static int find_if_case_1 (basic_block
, edge
, edge
);
108 static int find_if_case_2 (basic_block
, edge
, edge
);
109 static int find_memory (rtx
*, void *);
110 static int dead_or_predicable (basic_block
, basic_block
, basic_block
,
112 static void noce_emit_move_insn (rtx
, rtx
);
113 static rtx
block_has_only_trap (basic_block
);
115 /* Count the number of non-jump active insns in BB. */
118 count_bb_insns (basic_block bb
)
121 rtx insn
= BB_HEAD (bb
);
125 if (CALL_P (insn
) || NONJUMP_INSN_P (insn
))
128 if (insn
== BB_END (bb
))
130 insn
= NEXT_INSN (insn
);
136 /* Determine whether the total insn_rtx_cost on non-jump insns in
137 basic block BB is less than MAX_COST. This function returns
138 false if the cost of any instruction could not be estimated. */
141 cheap_bb_rtx_cost_p (basic_block bb
, int max_cost
)
144 rtx insn
= BB_HEAD (bb
);
148 if (NONJUMP_INSN_P (insn
))
150 int cost
= insn_rtx_cost (PATTERN (insn
));
154 /* If this instruction is the load or set of a "stack" register,
155 such as a floating point register on x87, then the cost of
156 speculatively executing this instruction needs to include
157 the additional cost of popping this register off of the
161 rtx set
= single_set (insn
);
162 if (set
&& STACK_REG_P (SET_DEST (set
)))
163 cost
+= COSTS_N_INSNS (1);
168 if (count
>= max_cost
)
171 else if (CALL_P (insn
))
174 if (insn
== BB_END (bb
))
176 insn
= NEXT_INSN (insn
);
182 /* Return the first non-jump active insn in the basic block. */
185 first_active_insn (basic_block bb
)
187 rtx insn
= BB_HEAD (bb
);
191 if (insn
== BB_END (bb
))
193 insn
= NEXT_INSN (insn
);
196 while (NOTE_P (insn
))
198 if (insn
== BB_END (bb
))
200 insn
= NEXT_INSN (insn
);
209 /* Return the last non-jump active (non-jump) insn in the basic block. */
212 last_active_insn (basic_block bb
, int skip_use_p
)
214 rtx insn
= BB_END (bb
);
215 rtx head
= BB_HEAD (bb
);
220 && NONJUMP_INSN_P (insn
)
221 && GET_CODE (PATTERN (insn
)) == USE
))
225 insn
= PREV_INSN (insn
);
234 /* Return the basic block reached by falling though the basic block BB. */
237 block_fallthru (basic_block bb
)
242 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
243 if (e
->flags
& EDGE_FALLTHRU
)
246 return (e
) ? e
->dest
: NULL_BLOCK
;
249 /* Go through a bunch of insns, converting them to conditional
250 execution format if possible. Return TRUE if all of the non-note
251 insns were processed. */
254 cond_exec_process_insns (ce_if_block_t
*ce_info ATTRIBUTE_UNUSED
,
255 /* if block information */rtx start
,
256 /* first insn to look at */rtx end
,
257 /* last insn to look at */rtx test
,
258 /* conditional execution test */rtx prob_val
,
259 /* probability of branch taken. */int mod_ok
)
261 int must_be_last
= FALSE
;
269 for (insn
= start
; ; insn
= NEXT_INSN (insn
))
274 gcc_assert(NONJUMP_INSN_P (insn
) || CALL_P (insn
));
276 /* Remove USE insns that get in the way. */
277 if (reload_completed
&& GET_CODE (PATTERN (insn
)) == USE
)
279 /* ??? Ug. Actually unlinking the thing is problematic,
280 given what we'd have to coordinate with our callers. */
281 SET_INSN_DELETED (insn
);
285 /* Last insn wasn't last? */
289 if (modified_in_p (test
, insn
))
296 /* Now build the conditional form of the instruction. */
297 pattern
= PATTERN (insn
);
298 xtest
= copy_rtx (test
);
300 /* If this is already a COND_EXEC, rewrite the test to be an AND of the
302 if (GET_CODE (pattern
) == COND_EXEC
)
304 if (GET_MODE (xtest
) != GET_MODE (COND_EXEC_TEST (pattern
)))
307 xtest
= gen_rtx_AND (GET_MODE (xtest
), xtest
,
308 COND_EXEC_TEST (pattern
));
309 pattern
= COND_EXEC_CODE (pattern
);
312 pattern
= gen_rtx_COND_EXEC (VOIDmode
, xtest
, pattern
);
314 /* If the machine needs to modify the insn being conditionally executed,
315 say for example to force a constant integer operand into a temp
316 register, do so here. */
317 #ifdef IFCVT_MODIFY_INSN
318 IFCVT_MODIFY_INSN (ce_info
, pattern
, insn
);
323 validate_change (insn
, &PATTERN (insn
), pattern
, 1);
325 if (CALL_P (insn
) && prob_val
)
326 validate_change (insn
, ®_NOTES (insn
),
327 alloc_EXPR_LIST (REG_BR_PROB
, prob_val
,
328 REG_NOTES (insn
)), 1);
338 /* Return the condition for a jump. Do not do any special processing. */
341 cond_exec_get_condition (rtx jump
)
345 if (any_condjump_p (jump
))
346 test_if
= SET_SRC (pc_set (jump
));
349 cond
= XEXP (test_if
, 0);
351 /* If this branches to JUMP_LABEL when the condition is false,
352 reverse the condition. */
353 if (GET_CODE (XEXP (test_if
, 2)) == LABEL_REF
354 && XEXP (XEXP (test_if
, 2), 0) == JUMP_LABEL (jump
))
356 enum rtx_code rev
= reversed_comparison_code (cond
, jump
);
360 cond
= gen_rtx_fmt_ee (rev
, GET_MODE (cond
), XEXP (cond
, 0),
367 /* Given a simple IF-THEN or IF-THEN-ELSE block, attempt to convert it
368 to conditional execution. Return TRUE if we were successful at
369 converting the block. */
372 cond_exec_process_if_block (ce_if_block_t
* ce_info
,
373 /* if block information */int do_multiple_p
)
375 basic_block test_bb
= ce_info
->test_bb
; /* last test block */
376 basic_block then_bb
= ce_info
->then_bb
; /* THEN */
377 basic_block else_bb
= ce_info
->else_bb
; /* ELSE or NULL */
378 rtx test_expr
; /* expression in IF_THEN_ELSE that is tested */
379 rtx then_start
; /* first insn in THEN block */
380 rtx then_end
; /* last insn + 1 in THEN block */
381 rtx else_start
= NULL_RTX
; /* first insn in ELSE block or NULL */
382 rtx else_end
= NULL_RTX
; /* last insn + 1 in ELSE block */
383 int max
; /* max # of insns to convert. */
384 int then_mod_ok
; /* whether conditional mods are ok in THEN */
385 rtx true_expr
; /* test for else block insns */
386 rtx false_expr
; /* test for then block insns */
387 rtx true_prob_val
; /* probability of else block */
388 rtx false_prob_val
; /* probability of then block */
390 enum rtx_code false_code
;
392 /* If test is comprised of && or || elements, and we've failed at handling
393 all of them together, just use the last test if it is the special case of
394 && elements without an ELSE block. */
395 if (!do_multiple_p
&& ce_info
->num_multiple_test_blocks
)
397 if (else_bb
|| ! ce_info
->and_and_p
)
400 ce_info
->test_bb
= test_bb
= ce_info
->last_test_bb
;
401 ce_info
->num_multiple_test_blocks
= 0;
402 ce_info
->num_and_and_blocks
= 0;
403 ce_info
->num_or_or_blocks
= 0;
406 /* Find the conditional jump to the ELSE or JOIN part, and isolate
408 test_expr
= cond_exec_get_condition (BB_END (test_bb
));
412 /* If the conditional jump is more than just a conditional jump,
413 then we can not do conditional execution conversion on this block. */
414 if (! onlyjump_p (BB_END (test_bb
)))
417 /* Collect the bounds of where we're to search, skipping any labels, jumps
418 and notes at the beginning and end of the block. Then count the total
419 number of insns and see if it is small enough to convert. */
420 then_start
= first_active_insn (then_bb
);
421 then_end
= last_active_insn (then_bb
, TRUE
);
422 n_insns
= ce_info
->num_then_insns
= count_bb_insns (then_bb
);
423 max
= MAX_CONDITIONAL_EXECUTE
;
428 else_start
= first_active_insn (else_bb
);
429 else_end
= last_active_insn (else_bb
, TRUE
);
430 n_insns
+= ce_info
->num_else_insns
= count_bb_insns (else_bb
);
436 /* Map test_expr/test_jump into the appropriate MD tests to use on
437 the conditionally executed code. */
439 true_expr
= test_expr
;
441 false_code
= reversed_comparison_code (true_expr
, BB_END (test_bb
));
442 if (false_code
!= UNKNOWN
)
443 false_expr
= gen_rtx_fmt_ee (false_code
, GET_MODE (true_expr
),
444 XEXP (true_expr
, 0), XEXP (true_expr
, 1));
446 false_expr
= NULL_RTX
;
448 #ifdef IFCVT_MODIFY_TESTS
449 /* If the machine description needs to modify the tests, such as setting a
450 conditional execution register from a comparison, it can do so here. */
451 IFCVT_MODIFY_TESTS (ce_info
, true_expr
, false_expr
);
453 /* See if the conversion failed. */
454 if (!true_expr
|| !false_expr
)
458 true_prob_val
= find_reg_note (BB_END (test_bb
), REG_BR_PROB
, NULL_RTX
);
461 true_prob_val
= XEXP (true_prob_val
, 0);
462 false_prob_val
= GEN_INT (REG_BR_PROB_BASE
- INTVAL (true_prob_val
));
465 false_prob_val
= NULL_RTX
;
467 /* If we have && or || tests, do them here. These tests are in the adjacent
468 blocks after the first block containing the test. */
469 if (ce_info
->num_multiple_test_blocks
> 0)
471 basic_block bb
= test_bb
;
472 basic_block last_test_bb
= ce_info
->last_test_bb
;
481 enum rtx_code f_code
;
483 bb
= block_fallthru (bb
);
484 start
= first_active_insn (bb
);
485 end
= last_active_insn (bb
, TRUE
);
487 && ! cond_exec_process_insns (ce_info
, start
, end
, false_expr
,
488 false_prob_val
, FALSE
))
491 /* If the conditional jump is more than just a conditional jump, then
492 we can not do conditional execution conversion on this block. */
493 if (! onlyjump_p (BB_END (bb
)))
496 /* Find the conditional jump and isolate the test. */
497 t
= cond_exec_get_condition (BB_END (bb
));
501 f_code
= reversed_comparison_code (t
, BB_END (bb
));
502 if (f_code
== UNKNOWN
)
505 f
= gen_rtx_fmt_ee (f_code
, GET_MODE (t
), XEXP (t
, 0), XEXP (t
, 1));
506 if (ce_info
->and_and_p
)
508 t
= gen_rtx_AND (GET_MODE (t
), true_expr
, t
);
509 f
= gen_rtx_IOR (GET_MODE (t
), false_expr
, f
);
513 t
= gen_rtx_IOR (GET_MODE (t
), true_expr
, t
);
514 f
= gen_rtx_AND (GET_MODE (t
), false_expr
, f
);
517 /* If the machine description needs to modify the tests, such as
518 setting a conditional execution register from a comparison, it can
520 #ifdef IFCVT_MODIFY_MULTIPLE_TESTS
521 IFCVT_MODIFY_MULTIPLE_TESTS (ce_info
, bb
, t
, f
);
523 /* See if the conversion failed. */
531 while (bb
!= last_test_bb
);
534 /* For IF-THEN-ELSE blocks, we don't allow modifications of the test
535 on then THEN block. */
536 then_mod_ok
= (else_bb
== NULL_BLOCK
);
538 /* Go through the THEN and ELSE blocks converting the insns if possible
539 to conditional execution. */
543 || ! cond_exec_process_insns (ce_info
, then_start
, then_end
,
544 false_expr
, false_prob_val
,
548 if (else_bb
&& else_end
549 && ! cond_exec_process_insns (ce_info
, else_start
, else_end
,
550 true_expr
, true_prob_val
, TRUE
))
553 /* If we cannot apply the changes, fail. Do not go through the normal fail
554 processing, since apply_change_group will call cancel_changes. */
555 if (! apply_change_group ())
557 #ifdef IFCVT_MODIFY_CANCEL
558 /* Cancel any machine dependent changes. */
559 IFCVT_MODIFY_CANCEL (ce_info
);
564 #ifdef IFCVT_MODIFY_FINAL
565 /* Do any machine dependent final modifications. */
566 IFCVT_MODIFY_FINAL (ce_info
);
569 /* Conversion succeeded. */
571 fprintf (dump_file
, "%d insn%s converted to conditional execution.\n",
572 n_insns
, (n_insns
== 1) ? " was" : "s were");
574 /* Merge the blocks! */
575 merge_if_block (ce_info
);
576 cond_exec_changed_p
= TRUE
;
580 #ifdef IFCVT_MODIFY_CANCEL
581 /* Cancel any machine dependent changes. */
582 IFCVT_MODIFY_CANCEL (ce_info
);
589 /* Used by noce_process_if_block to communicate with its subroutines.
591 The subroutines know that A and B may be evaluated freely. They
592 know that X is a register. They should insert new instructions
593 before cond_earliest. */
600 rtx jump
, cond
, cond_earliest
;
601 /* True if "b" was originally evaluated unconditionally. */
602 bool b_unconditional
;
605 static rtx
noce_emit_store_flag (struct noce_if_info
*, rtx
, int, int);
606 static int noce_try_move (struct noce_if_info
*);
607 static int noce_try_store_flag (struct noce_if_info
*);
608 static int noce_try_addcc (struct noce_if_info
*);
609 static int noce_try_store_flag_constants (struct noce_if_info
*);
610 static int noce_try_store_flag_mask (struct noce_if_info
*);
611 static rtx
noce_emit_cmove (struct noce_if_info
*, rtx
, enum rtx_code
, rtx
,
613 static int noce_try_cmove (struct noce_if_info
*);
614 static int noce_try_cmove_arith (struct noce_if_info
*);
615 static rtx
noce_get_alt_condition (struct noce_if_info
*, rtx
, rtx
*);
616 static int noce_try_minmax (struct noce_if_info
*);
617 static int noce_try_abs (struct noce_if_info
*);
618 static int noce_try_sign_mask (struct noce_if_info
*);
620 /* Helper function for noce_try_store_flag*. */
623 noce_emit_store_flag (struct noce_if_info
*if_info
, rtx x
, int reversep
,
626 rtx cond
= if_info
->cond
;
630 cond_complex
= (! general_operand (XEXP (cond
, 0), VOIDmode
)
631 || ! general_operand (XEXP (cond
, 1), VOIDmode
));
633 /* If earliest == jump, or when the condition is complex, try to
634 build the store_flag insn directly. */
637 cond
= XEXP (SET_SRC (pc_set (if_info
->jump
)), 0);
640 code
= reversed_comparison_code (cond
, if_info
->jump
);
642 code
= GET_CODE (cond
);
644 if ((if_info
->cond_earliest
== if_info
->jump
|| cond_complex
)
645 && (normalize
== 0 || STORE_FLAG_VALUE
== normalize
))
649 tmp
= gen_rtx_fmt_ee (code
, GET_MODE (x
), XEXP (cond
, 0),
651 tmp
= gen_rtx_SET (VOIDmode
, x
, tmp
);
654 tmp
= emit_insn (tmp
);
656 if (recog_memoized (tmp
) >= 0)
662 if_info
->cond_earliest
= if_info
->jump
;
670 /* Don't even try if the comparison operands or the mode of X are weird. */
671 if (cond_complex
|| !SCALAR_INT_MODE_P (GET_MODE (x
)))
674 return emit_store_flag (x
, code
, XEXP (cond
, 0),
675 XEXP (cond
, 1), VOIDmode
,
676 (code
== LTU
|| code
== LEU
677 || code
== GEU
|| code
== GTU
), normalize
);
680 /* Emit instruction to move an rtx, possibly into STRICT_LOW_PART.
681 X is the destination/target and Y is the value to copy. */
684 noce_emit_move_insn (rtx x
, rtx y
)
686 enum machine_mode outmode
;
690 if (GET_CODE (x
) != STRICT_LOW_PART
)
692 rtx seq
, insn
, target
;
696 /* Check that the SET_SRC is reasonable before calling emit_move_insn,
697 otherwise construct a suitable SET pattern ourselves. */
698 insn
= (OBJECT_P (y
) || CONSTANT_P (y
) || GET_CODE (y
) == SUBREG
)
699 ? emit_move_insn (x
, y
)
700 : emit_insn (gen_rtx_SET (VOIDmode
, x
, y
));
704 if (recog_memoized (insn
) <= 0)
705 switch (GET_RTX_CLASS (GET_CODE (y
)))
708 ot
= code_to_optab
[GET_CODE (y
)];
712 target
= expand_unop (GET_MODE (y
), ot
, XEXP (y
, 0), x
, 0);
713 if (target
!= NULL_RTX
)
716 emit_move_insn (x
, target
);
725 ot
= code_to_optab
[GET_CODE (y
)];
729 target
= expand_binop (GET_MODE (y
), ot
,
730 XEXP (y
, 0), XEXP (y
, 1),
732 if (target
!= NULL_RTX
)
735 emit_move_insn (x
, target
);
751 inner
= XEXP (outer
, 0);
752 outmode
= GET_MODE (outer
);
753 bitpos
= SUBREG_BYTE (outer
) * BITS_PER_UNIT
;
754 store_bit_field (inner
, GET_MODE_BITSIZE (outmode
), bitpos
, outmode
, y
);
757 /* Return sequence of instructions generated by if conversion. This
758 function calls end_sequence() to end the current stream, ensures
759 that are instructions are unshared, recognizable non-jump insns.
760 On failure, this function returns a NULL_RTX. */
763 end_ifcvt_sequence (struct noce_if_info
*if_info
)
766 rtx seq
= get_insns ();
768 set_used_flags (if_info
->x
);
769 set_used_flags (if_info
->cond
);
770 unshare_all_rtl_in_chain (seq
);
773 /* Make sure that all of the instructions emitted are recognizable,
774 and that we haven't introduced a new jump instruction.
775 As an exercise for the reader, build a general mechanism that
776 allows proper placement of required clobbers. */
777 for (insn
= seq
; insn
; insn
= NEXT_INSN (insn
))
779 || recog_memoized (insn
) == -1)
785 /* Convert "if (a != b) x = a; else x = b" into "x = a" and
786 "if (a == b) x = a; else x = b" into "x = b". */
789 noce_try_move (struct noce_if_info
*if_info
)
791 rtx cond
= if_info
->cond
;
792 enum rtx_code code
= GET_CODE (cond
);
795 if (code
!= NE
&& code
!= EQ
)
798 /* This optimization isn't valid if either A or B could be a NaN
800 if (HONOR_NANS (GET_MODE (if_info
->x
))
801 || HONOR_SIGNED_ZEROS (GET_MODE (if_info
->x
)))
804 /* Check whether the operands of the comparison are A and in
806 if ((rtx_equal_p (if_info
->a
, XEXP (cond
, 0))
807 && rtx_equal_p (if_info
->b
, XEXP (cond
, 1)))
808 || (rtx_equal_p (if_info
->a
, XEXP (cond
, 1))
809 && rtx_equal_p (if_info
->b
, XEXP (cond
, 0))))
811 y
= (code
== EQ
) ? if_info
->a
: if_info
->b
;
813 /* Avoid generating the move if the source is the destination. */
814 if (! rtx_equal_p (if_info
->x
, y
))
817 noce_emit_move_insn (if_info
->x
, y
);
818 seq
= end_ifcvt_sequence (if_info
);
822 emit_insn_before_setloc (seq
, if_info
->jump
,
823 INSN_LOCATOR (if_info
->insn_a
));
830 /* Convert "if (test) x = 1; else x = 0".
832 Only try 0 and STORE_FLAG_VALUE here. Other combinations will be
833 tried in noce_try_store_flag_constants after noce_try_cmove has had
834 a go at the conversion. */
837 noce_try_store_flag (struct noce_if_info
*if_info
)
842 if (GET_CODE (if_info
->b
) == CONST_INT
843 && INTVAL (if_info
->b
) == STORE_FLAG_VALUE
844 && if_info
->a
== const0_rtx
)
846 else if (if_info
->b
== const0_rtx
847 && GET_CODE (if_info
->a
) == CONST_INT
848 && INTVAL (if_info
->a
) == STORE_FLAG_VALUE
849 && (reversed_comparison_code (if_info
->cond
, if_info
->jump
)
857 target
= noce_emit_store_flag (if_info
, if_info
->x
, reversep
, 0);
860 if (target
!= if_info
->x
)
861 noce_emit_move_insn (if_info
->x
, target
);
863 seq
= end_ifcvt_sequence (if_info
);
867 emit_insn_before_setloc (seq
, if_info
->jump
,
868 INSN_LOCATOR (if_info
->insn_a
));
878 /* Convert "if (test) x = a; else x = b", for A and B constant. */
881 noce_try_store_flag_constants (struct noce_if_info
*if_info
)
885 HOST_WIDE_INT itrue
, ifalse
, diff
, tmp
;
886 int normalize
, can_reverse
;
887 enum machine_mode mode
;
890 && GET_CODE (if_info
->a
) == CONST_INT
891 && GET_CODE (if_info
->b
) == CONST_INT
)
893 mode
= GET_MODE (if_info
->x
);
894 ifalse
= INTVAL (if_info
->a
);
895 itrue
= INTVAL (if_info
->b
);
897 /* Make sure we can represent the difference between the two values. */
898 if ((itrue
- ifalse
> 0)
899 != ((ifalse
< 0) != (itrue
< 0) ? ifalse
< 0 : ifalse
< itrue
))
902 diff
= trunc_int_for_mode (itrue
- ifalse
, mode
);
904 can_reverse
= (reversed_comparison_code (if_info
->cond
, if_info
->jump
)
908 if (diff
== STORE_FLAG_VALUE
|| diff
== -STORE_FLAG_VALUE
)
910 else if (ifalse
== 0 && exact_log2 (itrue
) >= 0
911 && (STORE_FLAG_VALUE
== 1
912 || BRANCH_COST
>= 2))
914 else if (itrue
== 0 && exact_log2 (ifalse
) >= 0 && can_reverse
915 && (STORE_FLAG_VALUE
== 1 || BRANCH_COST
>= 2))
916 normalize
= 1, reversep
= 1;
918 && (STORE_FLAG_VALUE
== -1
919 || BRANCH_COST
>= 2))
921 else if (ifalse
== -1 && can_reverse
922 && (STORE_FLAG_VALUE
== -1 || BRANCH_COST
>= 2))
923 normalize
= -1, reversep
= 1;
924 else if ((BRANCH_COST
>= 2 && STORE_FLAG_VALUE
== -1)
932 tmp
= itrue
; itrue
= ifalse
; ifalse
= tmp
;
933 diff
= trunc_int_for_mode (-diff
, mode
);
937 target
= noce_emit_store_flag (if_info
, if_info
->x
, reversep
, normalize
);
944 /* if (test) x = 3; else x = 4;
945 => x = 3 + (test == 0); */
946 if (diff
== STORE_FLAG_VALUE
|| diff
== -STORE_FLAG_VALUE
)
948 target
= expand_simple_binop (mode
,
949 (diff
== STORE_FLAG_VALUE
951 GEN_INT (ifalse
), target
, if_info
->x
, 0,
955 /* if (test) x = 8; else x = 0;
956 => x = (test != 0) << 3; */
957 else if (ifalse
== 0 && (tmp
= exact_log2 (itrue
)) >= 0)
959 target
= expand_simple_binop (mode
, ASHIFT
,
960 target
, GEN_INT (tmp
), if_info
->x
, 0,
964 /* if (test) x = -1; else x = b;
965 => x = -(test != 0) | b; */
966 else if (itrue
== -1)
968 target
= expand_simple_binop (mode
, IOR
,
969 target
, GEN_INT (ifalse
), if_info
->x
, 0,
973 /* if (test) x = a; else x = b;
974 => x = (-(test != 0) & (b - a)) + a; */
977 target
= expand_simple_binop (mode
, AND
,
978 target
, GEN_INT (diff
), if_info
->x
, 0,
981 target
= expand_simple_binop (mode
, PLUS
,
982 target
, GEN_INT (ifalse
),
983 if_info
->x
, 0, OPTAB_WIDEN
);
992 if (target
!= if_info
->x
)
993 noce_emit_move_insn (if_info
->x
, target
);
995 seq
= end_ifcvt_sequence (if_info
);
999 emit_insn_before_setloc (seq
, if_info
->jump
,
1000 INSN_LOCATOR (if_info
->insn_a
));
1007 /* Convert "if (test) foo++" into "foo += (test != 0)", and
1008 similarly for "foo--". */
1011 noce_try_addcc (struct noce_if_info
*if_info
)
1014 int subtract
, normalize
;
1016 if (! no_new_pseudos
1017 && GET_CODE (if_info
->a
) == PLUS
1018 && rtx_equal_p (XEXP (if_info
->a
, 0), if_info
->b
)
1019 && (reversed_comparison_code (if_info
->cond
, if_info
->jump
)
1022 rtx cond
= if_info
->cond
;
1023 enum rtx_code code
= reversed_comparison_code (cond
, if_info
->jump
);
1025 /* First try to use addcc pattern. */
1026 if (general_operand (XEXP (cond
, 0), VOIDmode
)
1027 && general_operand (XEXP (cond
, 1), VOIDmode
))
1030 target
= emit_conditional_add (if_info
->x
, code
,
1035 XEXP (if_info
->a
, 1),
1036 GET_MODE (if_info
->x
),
1037 (code
== LTU
|| code
== GEU
1038 || code
== LEU
|| code
== GTU
));
1041 if (target
!= if_info
->x
)
1042 noce_emit_move_insn (if_info
->x
, target
);
1044 seq
= end_ifcvt_sequence (if_info
);
1048 emit_insn_before_setloc (seq
, if_info
->jump
,
1049 INSN_LOCATOR (if_info
->insn_a
));
1055 /* If that fails, construct conditional increment or decrement using
1057 if (BRANCH_COST
>= 2
1058 && (XEXP (if_info
->a
, 1) == const1_rtx
1059 || XEXP (if_info
->a
, 1) == constm1_rtx
))
1062 if (STORE_FLAG_VALUE
== INTVAL (XEXP (if_info
->a
, 1)))
1063 subtract
= 0, normalize
= 0;
1064 else if (-STORE_FLAG_VALUE
== INTVAL (XEXP (if_info
->a
, 1)))
1065 subtract
= 1, normalize
= 0;
1067 subtract
= 0, normalize
= INTVAL (XEXP (if_info
->a
, 1));
1070 target
= noce_emit_store_flag (if_info
,
1071 gen_reg_rtx (GET_MODE (if_info
->x
)),
1075 target
= expand_simple_binop (GET_MODE (if_info
->x
),
1076 subtract
? MINUS
: PLUS
,
1077 if_info
->b
, target
, if_info
->x
,
1081 if (target
!= if_info
->x
)
1082 noce_emit_move_insn (if_info
->x
, target
);
1084 seq
= end_ifcvt_sequence (if_info
);
1088 emit_insn_before_setloc (seq
, if_info
->jump
,
1089 INSN_LOCATOR (if_info
->insn_a
));
1099 /* Convert "if (test) x = 0;" to "x &= -(test == 0);" */
1102 noce_try_store_flag_mask (struct noce_if_info
*if_info
)
1108 if (! no_new_pseudos
1109 && (BRANCH_COST
>= 2
1110 || STORE_FLAG_VALUE
== -1)
1111 && ((if_info
->a
== const0_rtx
1112 && rtx_equal_p (if_info
->b
, if_info
->x
))
1113 || ((reversep
= (reversed_comparison_code (if_info
->cond
,
1116 && if_info
->b
== const0_rtx
1117 && rtx_equal_p (if_info
->a
, if_info
->x
))))
1120 target
= noce_emit_store_flag (if_info
,
1121 gen_reg_rtx (GET_MODE (if_info
->x
)),
1124 target
= expand_simple_binop (GET_MODE (if_info
->x
), AND
,
1126 target
, if_info
->x
, 0,
1131 if (target
!= if_info
->x
)
1132 noce_emit_move_insn (if_info
->x
, target
);
1134 seq
= end_ifcvt_sequence (if_info
);
1138 emit_insn_before_setloc (seq
, if_info
->jump
,
1139 INSN_LOCATOR (if_info
->insn_a
));
1149 /* Helper function for noce_try_cmove and noce_try_cmove_arith. */
1152 noce_emit_cmove (struct noce_if_info
*if_info
, rtx x
, enum rtx_code code
,
1153 rtx cmp_a
, rtx cmp_b
, rtx vfalse
, rtx vtrue
)
1155 /* If earliest == jump, try to build the cmove insn directly.
1156 This is helpful when combine has created some complex condition
1157 (like for alpha's cmovlbs) that we can't hope to regenerate
1158 through the normal interface. */
1160 if (if_info
->cond_earliest
== if_info
->jump
)
1164 tmp
= gen_rtx_fmt_ee (code
, GET_MODE (if_info
->cond
), cmp_a
, cmp_b
);
1165 tmp
= gen_rtx_IF_THEN_ELSE (GET_MODE (x
), tmp
, vtrue
, vfalse
);
1166 tmp
= gen_rtx_SET (VOIDmode
, x
, tmp
);
1169 tmp
= emit_insn (tmp
);
1171 if (recog_memoized (tmp
) >= 0)
1183 /* Don't even try if the comparison operands are weird. */
1184 if (! general_operand (cmp_a
, GET_MODE (cmp_a
))
1185 || ! general_operand (cmp_b
, GET_MODE (cmp_b
)))
1188 #if HAVE_conditional_move
1189 return emit_conditional_move (x
, code
, cmp_a
, cmp_b
, VOIDmode
,
1190 vtrue
, vfalse
, GET_MODE (x
),
1191 (code
== LTU
|| code
== GEU
1192 || code
== LEU
|| code
== GTU
));
1194 /* We'll never get here, as noce_process_if_block doesn't call the
1195 functions involved. Ifdef code, however, should be discouraged
1196 because it leads to typos in the code not selected. However,
1197 emit_conditional_move won't exist either. */
1202 /* Try only simple constants and registers here. More complex cases
1203 are handled in noce_try_cmove_arith after noce_try_store_flag_arith
1204 has had a go at it. */
1207 noce_try_cmove (struct noce_if_info
*if_info
)
1212 if ((CONSTANT_P (if_info
->a
) || register_operand (if_info
->a
, VOIDmode
))
1213 && (CONSTANT_P (if_info
->b
) || register_operand (if_info
->b
, VOIDmode
)))
1217 code
= GET_CODE (if_info
->cond
);
1218 target
= noce_emit_cmove (if_info
, if_info
->x
, code
,
1219 XEXP (if_info
->cond
, 0),
1220 XEXP (if_info
->cond
, 1),
1221 if_info
->a
, if_info
->b
);
1225 if (target
!= if_info
->x
)
1226 noce_emit_move_insn (if_info
->x
, target
);
1228 seq
= end_ifcvt_sequence (if_info
);
1232 emit_insn_before_setloc (seq
, if_info
->jump
,
1233 INSN_LOCATOR (if_info
->insn_a
));
1246 /* Try more complex cases involving conditional_move. */
1249 noce_try_cmove_arith (struct noce_if_info
*if_info
)
1261 /* A conditional move from two memory sources is equivalent to a
1262 conditional on their addresses followed by a load. Don't do this
1263 early because it'll screw alias analysis. Note that we've
1264 already checked for no side effects. */
1265 if (! no_new_pseudos
&& cse_not_expected
1266 && MEM_P (a
) && MEM_P (b
)
1267 && BRANCH_COST
>= 5)
1271 x
= gen_reg_rtx (Pmode
);
1275 /* ??? We could handle this if we knew that a load from A or B could
1276 not fault. This is also true if we've already loaded
1277 from the address along the path from ENTRY. */
1278 else if (may_trap_p (a
) || may_trap_p (b
))
1281 /* if (test) x = a + b; else x = c - d;
1288 code
= GET_CODE (if_info
->cond
);
1289 insn_a
= if_info
->insn_a
;
1290 insn_b
= if_info
->insn_b
;
1292 /* Total insn_rtx_cost should be smaller than branch cost. Exit
1293 if insn_rtx_cost can't be estimated. */
1296 insn_cost
= insn_rtx_cost (PATTERN (insn_a
));
1297 if (insn_cost
== 0 || insn_cost
> COSTS_N_INSNS (BRANCH_COST
))
1306 insn_cost
+= insn_rtx_cost (PATTERN (insn_b
));
1307 if (insn_cost
== 0 || insn_cost
> COSTS_N_INSNS (BRANCH_COST
))
1311 /* Possibly rearrange operands to make things come out more natural. */
1312 if (reversed_comparison_code (if_info
->cond
, if_info
->jump
) != UNKNOWN
)
1315 if (rtx_equal_p (b
, x
))
1317 else if (general_operand (b
, GET_MODE (b
)))
1322 code
= reversed_comparison_code (if_info
->cond
, if_info
->jump
);
1323 tmp
= a
, a
= b
, b
= tmp
;
1324 tmp
= insn_a
, insn_a
= insn_b
, insn_b
= tmp
;
1333 /* If either operand is complex, load it into a register first.
1334 The best way to do this is to copy the original insn. In this
1335 way we preserve any clobbers etc that the insn may have had.
1336 This is of course not possible in the IS_MEM case. */
1337 if (! general_operand (a
, GET_MODE (a
)))
1342 goto end_seq_and_fail
;
1346 tmp
= gen_reg_rtx (GET_MODE (a
));
1347 tmp
= emit_insn (gen_rtx_SET (VOIDmode
, tmp
, a
));
1350 goto end_seq_and_fail
;
1353 a
= gen_reg_rtx (GET_MODE (a
));
1354 tmp
= copy_rtx (insn_a
);
1355 set
= single_set (tmp
);
1357 tmp
= emit_insn (PATTERN (tmp
));
1359 if (recog_memoized (tmp
) < 0)
1360 goto end_seq_and_fail
;
1362 if (! general_operand (b
, GET_MODE (b
)))
1367 goto end_seq_and_fail
;
1371 tmp
= gen_reg_rtx (GET_MODE (b
));
1372 tmp
= gen_rtx_SET (VOIDmode
, tmp
, b
);
1375 goto end_seq_and_fail
;
1378 b
= gen_reg_rtx (GET_MODE (b
));
1379 tmp
= copy_rtx (insn_b
);
1380 set
= single_set (tmp
);
1382 tmp
= PATTERN (tmp
);
1385 /* If insn to set up A clobbers any registers B depends on, try to
1386 swap insn that sets up A with the one that sets up B. If even
1387 that doesn't help, punt. */
1388 last
= get_last_insn ();
1389 if (last
&& modified_in_p (orig_b
, last
))
1391 tmp
= emit_insn_before (tmp
, get_insns ());
1392 if (modified_in_p (orig_a
, tmp
))
1393 goto end_seq_and_fail
;
1396 tmp
= emit_insn (tmp
);
1398 if (recog_memoized (tmp
) < 0)
1399 goto end_seq_and_fail
;
1402 target
= noce_emit_cmove (if_info
, x
, code
, XEXP (if_info
->cond
, 0),
1403 XEXP (if_info
->cond
, 1), a
, b
);
1406 goto end_seq_and_fail
;
1408 /* If we're handling a memory for above, emit the load now. */
1411 tmp
= gen_rtx_MEM (GET_MODE (if_info
->x
), target
);
1413 /* Copy over flags as appropriate. */
1414 if (MEM_VOLATILE_P (if_info
->a
) || MEM_VOLATILE_P (if_info
->b
))
1415 MEM_VOLATILE_P (tmp
) = 1;
1416 if (MEM_IN_STRUCT_P (if_info
->a
) && MEM_IN_STRUCT_P (if_info
->b
))
1417 MEM_IN_STRUCT_P (tmp
) = 1;
1418 if (MEM_SCALAR_P (if_info
->a
) && MEM_SCALAR_P (if_info
->b
))
1419 MEM_SCALAR_P (tmp
) = 1;
1420 if (MEM_ALIAS_SET (if_info
->a
) == MEM_ALIAS_SET (if_info
->b
))
1421 set_mem_alias_set (tmp
, MEM_ALIAS_SET (if_info
->a
));
1423 MIN (MEM_ALIGN (if_info
->a
), MEM_ALIGN (if_info
->b
)));
1425 noce_emit_move_insn (if_info
->x
, tmp
);
1427 else if (target
!= x
)
1428 noce_emit_move_insn (x
, target
);
1430 tmp
= end_ifcvt_sequence (if_info
);
1434 emit_insn_before_setloc (tmp
, if_info
->jump
, INSN_LOCATOR (if_info
->insn_a
));
1442 /* For most cases, the simplified condition we found is the best
1443 choice, but this is not the case for the min/max/abs transforms.
1444 For these we wish to know that it is A or B in the condition. */
1447 noce_get_alt_condition (struct noce_if_info
*if_info
, rtx target
,
1450 rtx cond
, set
, insn
;
1453 /* If target is already mentioned in the known condition, return it. */
1454 if (reg_mentioned_p (target
, if_info
->cond
))
1456 *earliest
= if_info
->cond_earliest
;
1457 return if_info
->cond
;
1460 set
= pc_set (if_info
->jump
);
1461 cond
= XEXP (SET_SRC (set
), 0);
1463 = GET_CODE (XEXP (SET_SRC (set
), 2)) == LABEL_REF
1464 && XEXP (XEXP (SET_SRC (set
), 2), 0) == JUMP_LABEL (if_info
->jump
);
1466 /* If we're looking for a constant, try to make the conditional
1467 have that constant in it. There are two reasons why it may
1468 not have the constant we want:
1470 1. GCC may have needed to put the constant in a register, because
1471 the target can't compare directly against that constant. For
1472 this case, we look for a SET immediately before the comparison
1473 that puts a constant in that register.
1475 2. GCC may have canonicalized the conditional, for example
1476 replacing "if x < 4" with "if x <= 3". We can undo that (or
1477 make equivalent types of changes) to get the constants we need
1478 if they're off by one in the right direction. */
1480 if (GET_CODE (target
) == CONST_INT
)
1482 enum rtx_code code
= GET_CODE (if_info
->cond
);
1483 rtx op_a
= XEXP (if_info
->cond
, 0);
1484 rtx op_b
= XEXP (if_info
->cond
, 1);
1487 /* First, look to see if we put a constant in a register. */
1488 prev_insn
= prev_nonnote_insn (if_info
->cond_earliest
);
1490 && INSN_P (prev_insn
)
1491 && GET_CODE (PATTERN (prev_insn
)) == SET
)
1493 rtx src
= find_reg_equal_equiv_note (prev_insn
);
1495 src
= SET_SRC (PATTERN (prev_insn
));
1496 if (GET_CODE (src
) == CONST_INT
)
1498 if (rtx_equal_p (op_a
, SET_DEST (PATTERN (prev_insn
))))
1500 else if (rtx_equal_p (op_b
, SET_DEST (PATTERN (prev_insn
))))
1503 if (GET_CODE (op_a
) == CONST_INT
)
1508 code
= swap_condition (code
);
1513 /* Now, look to see if we can get the right constant by
1514 adjusting the conditional. */
1515 if (GET_CODE (op_b
) == CONST_INT
)
1517 HOST_WIDE_INT desired_val
= INTVAL (target
);
1518 HOST_WIDE_INT actual_val
= INTVAL (op_b
);
1523 if (actual_val
== desired_val
+ 1)
1526 op_b
= GEN_INT (desired_val
);
1530 if (actual_val
== desired_val
- 1)
1533 op_b
= GEN_INT (desired_val
);
1537 if (actual_val
== desired_val
- 1)
1540 op_b
= GEN_INT (desired_val
);
1544 if (actual_val
== desired_val
+ 1)
1547 op_b
= GEN_INT (desired_val
);
1555 /* If we made any changes, generate a new conditional that is
1556 equivalent to what we started with, but has the right
1558 if (code
!= GET_CODE (if_info
->cond
)
1559 || op_a
!= XEXP (if_info
->cond
, 0)
1560 || op_b
!= XEXP (if_info
->cond
, 1))
1562 cond
= gen_rtx_fmt_ee (code
, GET_MODE (cond
), op_a
, op_b
);
1563 *earliest
= if_info
->cond_earliest
;
1568 cond
= canonicalize_condition (if_info
->jump
, cond
, reverse
,
1569 earliest
, target
, false, true);
1570 if (! cond
|| ! reg_mentioned_p (target
, cond
))
1573 /* We almost certainly searched back to a different place.
1574 Need to re-verify correct lifetimes. */
1576 /* X may not be mentioned in the range (cond_earliest, jump]. */
1577 for (insn
= if_info
->jump
; insn
!= *earliest
; insn
= PREV_INSN (insn
))
1578 if (INSN_P (insn
) && reg_overlap_mentioned_p (if_info
->x
, PATTERN (insn
)))
1581 /* A and B may not be modified in the range [cond_earliest, jump). */
1582 for (insn
= *earliest
; insn
!= if_info
->jump
; insn
= NEXT_INSN (insn
))
1584 && (modified_in_p (if_info
->a
, insn
)
1585 || modified_in_p (if_info
->b
, insn
)))
1591 /* Convert "if (a < b) x = a; else x = b;" to "x = min(a, b);", etc. */
1594 noce_try_minmax (struct noce_if_info
*if_info
)
1596 rtx cond
, earliest
, target
, seq
;
1597 enum rtx_code code
, op
;
1600 /* ??? Can't guarantee that expand_binop won't create pseudos. */
1604 /* ??? Reject modes with NaNs or signed zeros since we don't know how
1605 they will be resolved with an SMIN/SMAX. It wouldn't be too hard
1606 to get the target to tell us... */
1607 if (HONOR_SIGNED_ZEROS (GET_MODE (if_info
->x
))
1608 || HONOR_NANS (GET_MODE (if_info
->x
)))
1611 cond
= noce_get_alt_condition (if_info
, if_info
->a
, &earliest
);
1615 /* Verify the condition is of the form we expect, and canonicalize
1616 the comparison code. */
1617 code
= GET_CODE (cond
);
1618 if (rtx_equal_p (XEXP (cond
, 0), if_info
->a
))
1620 if (! rtx_equal_p (XEXP (cond
, 1), if_info
->b
))
1623 else if (rtx_equal_p (XEXP (cond
, 1), if_info
->a
))
1625 if (! rtx_equal_p (XEXP (cond
, 0), if_info
->b
))
1627 code
= swap_condition (code
);
1632 /* Determine what sort of operation this is. Note that the code is for
1633 a taken branch, so the code->operation mapping appears backwards. */
1666 target
= expand_simple_binop (GET_MODE (if_info
->x
), op
,
1667 if_info
->a
, if_info
->b
,
1668 if_info
->x
, unsignedp
, OPTAB_WIDEN
);
1674 if (target
!= if_info
->x
)
1675 noce_emit_move_insn (if_info
->x
, target
);
1677 seq
= end_ifcvt_sequence (if_info
);
1681 emit_insn_before_setloc (seq
, if_info
->jump
, INSN_LOCATOR (if_info
->insn_a
));
1682 if_info
->cond
= cond
;
1683 if_info
->cond_earliest
= earliest
;
1688 /* Convert "if (a < 0) x = -a; else x = a;" to "x = abs(a);", etc. */
1691 noce_try_abs (struct noce_if_info
*if_info
)
1693 rtx cond
, earliest
, target
, seq
, a
, b
, c
;
1696 /* ??? Can't guarantee that expand_binop won't create pseudos. */
1700 /* Recognize A and B as constituting an ABS or NABS. The canonical
1701 form is a branch around the negation, taken when the object is the
1702 first operand of a comparison against 0 that evaluates to true. */
1705 if (GET_CODE (a
) == NEG
&& rtx_equal_p (XEXP (a
, 0), b
))
1707 else if (GET_CODE (b
) == NEG
&& rtx_equal_p (XEXP (b
, 0), a
))
1709 c
= a
; a
= b
; b
= c
;
1715 cond
= noce_get_alt_condition (if_info
, b
, &earliest
);
1719 /* Verify the condition is of the form we expect. */
1720 if (rtx_equal_p (XEXP (cond
, 0), b
))
1722 else if (rtx_equal_p (XEXP (cond
, 1), b
))
1730 /* Verify that C is zero. Search one step backward for a
1731 REG_EQUAL note or a simple source if necessary. */
1734 rtx set
, insn
= prev_nonnote_insn (earliest
);
1736 && (set
= single_set (insn
))
1737 && rtx_equal_p (SET_DEST (set
), c
))
1739 rtx note
= find_reg_equal_equiv_note (insn
);
1749 && GET_CODE (XEXP (c
, 0)) == SYMBOL_REF
1750 && CONSTANT_POOL_ADDRESS_P (XEXP (c
, 0)))
1751 c
= get_pool_constant (XEXP (c
, 0));
1753 /* Work around funny ideas get_condition has wrt canonicalization.
1754 Note that these rtx constants are known to be CONST_INT, and
1755 therefore imply integer comparisons. */
1756 if (c
== constm1_rtx
&& GET_CODE (cond
) == GT
)
1758 else if (c
== const1_rtx
&& GET_CODE (cond
) == LT
)
1760 else if (c
!= CONST0_RTX (GET_MODE (b
)))
1763 /* Determine what sort of operation this is. */
1764 switch (GET_CODE (cond
))
1783 target
= expand_abs_nojump (GET_MODE (if_info
->x
), b
, if_info
->x
, 1);
1785 /* ??? It's a quandary whether cmove would be better here, especially
1786 for integers. Perhaps combine will clean things up. */
1787 if (target
&& negate
)
1788 target
= expand_simple_unop (GET_MODE (target
), NEG
, target
, if_info
->x
, 0);
1796 if (target
!= if_info
->x
)
1797 noce_emit_move_insn (if_info
->x
, target
);
1799 seq
= end_ifcvt_sequence (if_info
);
1803 emit_insn_before_setloc (seq
, if_info
->jump
, INSN_LOCATOR (if_info
->insn_a
));
1804 if_info
->cond
= cond
;
1805 if_info
->cond_earliest
= earliest
;
1810 /* Convert "if (m < 0) x = b; else x = 0;" to "x = (m >> C) & b;". */
1813 noce_try_sign_mask (struct noce_if_info
*if_info
)
1815 rtx cond
, t
, m
, c
, seq
;
1816 enum machine_mode mode
;
1822 cond
= if_info
->cond
;
1823 code
= GET_CODE (cond
);
1828 if (if_info
->a
== const0_rtx
)
1830 if ((code
== LT
&& c
== const0_rtx
)
1831 || (code
== LE
&& c
== constm1_rtx
))
1834 else if (if_info
->b
== const0_rtx
)
1836 if ((code
== GE
&& c
== const0_rtx
)
1837 || (code
== GT
&& c
== constm1_rtx
))
1841 if (! t
|| side_effects_p (t
))
1844 /* We currently don't handle different modes. */
1845 mode
= GET_MODE (t
);
1846 if (GET_MODE (m
) != mode
)
1849 /* This is only profitable if T is cheap, or T is unconditionally
1850 executed/evaluated in the original insn sequence. */
1851 if (rtx_cost (t
, SET
) >= COSTS_N_INSNS (2)
1852 && (!if_info
->b_unconditional
1853 || t
!= if_info
->b
))
1857 /* Use emit_store_flag to generate "m < 0 ? -1 : 0" instead of expanding
1858 "(signed) m >> 31" directly. This benefits targets with specialized
1859 insns to obtain the signmask, but still uses ashr_optab otherwise. */
1860 m
= emit_store_flag (gen_reg_rtx (mode
), LT
, m
, const0_rtx
, mode
, 0, -1);
1861 t
= m
? expand_binop (mode
, and_optab
, m
, t
, NULL_RTX
, 0, OPTAB_DIRECT
)
1870 noce_emit_move_insn (if_info
->x
, t
);
1872 seq
= end_ifcvt_sequence (if_info
);
1876 emit_insn_before_setloc (seq
, if_info
->jump
, INSN_LOCATOR (if_info
->insn_a
));
1881 /* Optimize away "if (x & C) x |= C" and similar bit manipulation
1885 noce_try_bitop (struct noce_if_info
*if_info
)
1887 rtx cond
, x
, a
, result
, seq
;
1888 enum machine_mode mode
;
1893 cond
= if_info
->cond
;
1894 code
= GET_CODE (cond
);
1896 /* Check for no else condition. */
1897 if (! rtx_equal_p (x
, if_info
->b
))
1900 /* Check for a suitable condition. */
1901 if (code
!= NE
&& code
!= EQ
)
1903 if (XEXP (cond
, 1) != const0_rtx
)
1905 cond
= XEXP (cond
, 0);
1907 /* ??? We could also handle AND here. */
1908 if (GET_CODE (cond
) == ZERO_EXTRACT
)
1910 if (XEXP (cond
, 1) != const1_rtx
1911 || GET_CODE (XEXP (cond
, 2)) != CONST_INT
1912 || ! rtx_equal_p (x
, XEXP (cond
, 0)))
1914 bitnum
= INTVAL (XEXP (cond
, 2));
1915 mode
= GET_MODE (x
);
1916 if (bitnum
>= HOST_BITS_PER_WIDE_INT
)
1923 if (GET_CODE (a
) == IOR
|| GET_CODE (a
) == XOR
)
1925 /* Check for "if (X & C) x = x op C". */
1926 if (! rtx_equal_p (x
, XEXP (a
, 0))
1927 || GET_CODE (XEXP (a
, 1)) != CONST_INT
1928 || (INTVAL (XEXP (a
, 1)) & GET_MODE_MASK (mode
))
1929 != (unsigned HOST_WIDE_INT
) 1 << bitnum
)
1932 /* if ((x & C) == 0) x |= C; is transformed to x |= C. */
1933 /* if ((x & C) != 0) x |= C; is transformed to nothing. */
1934 if (GET_CODE (a
) == IOR
)
1935 result
= (code
== NE
) ? a
: NULL_RTX
;
1936 else if (code
== NE
)
1938 /* if ((x & C) == 0) x ^= C; is transformed to x |= C. */
1939 result
= gen_int_mode ((HOST_WIDE_INT
) 1 << bitnum
, mode
);
1940 result
= simplify_gen_binary (IOR
, mode
, x
, result
);
1944 /* if ((x & C) != 0) x ^= C; is transformed to x &= ~C. */
1945 result
= gen_int_mode (~((HOST_WIDE_INT
) 1 << bitnum
), mode
);
1946 result
= simplify_gen_binary (AND
, mode
, x
, result
);
1949 else if (GET_CODE (a
) == AND
)
1951 /* Check for "if (X & C) x &= ~C". */
1952 if (! rtx_equal_p (x
, XEXP (a
, 0))
1953 || GET_CODE (XEXP (a
, 1)) != CONST_INT
1954 || (INTVAL (XEXP (a
, 1)) & GET_MODE_MASK (mode
))
1955 != (~((HOST_WIDE_INT
) 1 << bitnum
) & GET_MODE_MASK (mode
)))
1958 /* if ((x & C) == 0) x &= ~C; is transformed to nothing. */
1959 /* if ((x & C) != 0) x &= ~C; is transformed to x &= ~C. */
1960 result
= (code
== EQ
) ? a
: NULL_RTX
;
1968 noce_emit_move_insn (x
, result
);
1969 seq
= end_ifcvt_sequence (if_info
);
1973 emit_insn_before_setloc (seq
, if_info
->jump
,
1974 INSN_LOCATOR (if_info
->insn_a
));
1980 /* Similar to get_condition, only the resulting condition must be
1981 valid at JUMP, instead of at EARLIEST. */
1984 noce_get_condition (rtx jump
, rtx
*earliest
)
1989 if (! any_condjump_p (jump
))
1992 set
= pc_set (jump
);
1994 /* If this branches to JUMP_LABEL when the condition is false,
1995 reverse the condition. */
1996 reverse
= (GET_CODE (XEXP (SET_SRC (set
), 2)) == LABEL_REF
1997 && XEXP (XEXP (SET_SRC (set
), 2), 0) == JUMP_LABEL (jump
));
1999 /* If the condition variable is a register and is MODE_INT, accept it. */
2001 cond
= XEXP (SET_SRC (set
), 0);
2002 tmp
= XEXP (cond
, 0);
2003 if (REG_P (tmp
) && GET_MODE_CLASS (GET_MODE (tmp
)) == MODE_INT
)
2008 cond
= gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond
)),
2009 GET_MODE (cond
), tmp
, XEXP (cond
, 1));
2013 /* Otherwise, fall back on canonicalize_condition to do the dirty
2014 work of manipulating MODE_CC values and COMPARE rtx codes. */
2015 return canonicalize_condition (jump
, cond
, reverse
, earliest
,
2016 NULL_RTX
, false, true);
2019 /* Return true if OP is ok for if-then-else processing. */
2022 noce_operand_ok (rtx op
)
2024 /* We special-case memories, so handle any of them with
2025 no address side effects. */
2027 return ! side_effects_p (XEXP (op
, 0));
2029 if (side_effects_p (op
))
2032 return ! may_trap_p (op
);
2035 /* Return true if a write into MEM may trap or fault. */
2038 noce_mem_write_may_trap_or_fault_p (rtx mem
)
2042 if (MEM_READONLY_P (mem
))
2045 if (may_trap_or_fault_p (mem
))
2048 addr
= XEXP (mem
, 0);
2050 /* Call target hook to avoid the effects of -fpic etc.... */
2051 addr
= targetm
.delegitimize_address (addr
);
2054 switch (GET_CODE (addr
))
2062 addr
= XEXP (addr
, 0);
2066 addr
= XEXP (addr
, 1);
2069 if (GET_CODE (XEXP (addr
, 1)) == CONST_INT
)
2070 addr
= XEXP (addr
, 0);
2077 if (SYMBOL_REF_DECL (addr
)
2078 && decl_readonly_section (SYMBOL_REF_DECL (addr
), 0))
2088 /* Given a simple IF-THEN or IF-THEN-ELSE block, attempt to convert it
2089 without using conditional execution. Return TRUE if we were
2090 successful at converting the block. */
2093 noce_process_if_block (struct ce_if_block
* ce_info
)
2095 basic_block test_bb
= ce_info
->test_bb
; /* test block */
2096 basic_block then_bb
= ce_info
->then_bb
; /* THEN */
2097 basic_block else_bb
= ce_info
->else_bb
; /* ELSE or NULL */
2098 struct noce_if_info if_info
;
2101 rtx orig_x
, x
, a
, b
;
2104 /* We're looking for patterns of the form
2106 (1) if (...) x = a; else x = b;
2107 (2) x = b; if (...) x = a;
2108 (3) if (...) x = a; // as if with an initial x = x.
2110 The later patterns require jumps to be more expensive.
2112 ??? For future expansion, look for multiple X in such patterns. */
2114 /* If test is comprised of && or || elements, don't handle it unless it is
2115 the special case of && elements without an ELSE block. */
2116 if (ce_info
->num_multiple_test_blocks
)
2118 if (else_bb
|| ! ce_info
->and_and_p
)
2121 ce_info
->test_bb
= test_bb
= ce_info
->last_test_bb
;
2122 ce_info
->num_multiple_test_blocks
= 0;
2123 ce_info
->num_and_and_blocks
= 0;
2124 ce_info
->num_or_or_blocks
= 0;
2127 /* If this is not a standard conditional jump, we can't parse it. */
2128 jump
= BB_END (test_bb
);
2129 cond
= noce_get_condition (jump
, &if_info
.cond_earliest
);
2133 /* If the conditional jump is more than just a conditional
2134 jump, then we can not do if-conversion on this block. */
2135 if (! onlyjump_p (jump
))
2138 /* We must be comparing objects whose modes imply the size. */
2139 if (GET_MODE (XEXP (cond
, 0)) == BLKmode
)
2142 /* Look for one of the potential sets. */
2143 insn_a
= first_active_insn (then_bb
);
2145 || insn_a
!= last_active_insn (then_bb
, FALSE
)
2146 || (set_a
= single_set (insn_a
)) == NULL_RTX
)
2149 x
= SET_DEST (set_a
);
2150 a
= SET_SRC (set_a
);
2152 /* Look for the other potential set. Make sure we've got equivalent
2154 /* ??? This is overconservative. Storing to two different mems is
2155 as easy as conditionally computing the address. Storing to a
2156 single mem merely requires a scratch memory to use as one of the
2157 destination addresses; often the memory immediately below the
2158 stack pointer is available for this. */
2162 insn_b
= first_active_insn (else_bb
);
2164 || insn_b
!= last_active_insn (else_bb
, FALSE
)
2165 || (set_b
= single_set (insn_b
)) == NULL_RTX
2166 || ! rtx_equal_p (x
, SET_DEST (set_b
)))
2171 insn_b
= prev_nonnote_insn (if_info
.cond_earliest
);
2172 /* We're going to be moving the evaluation of B down from above
2173 COND_EARLIEST to JUMP. Make sure the relevant data is still
2176 || !NONJUMP_INSN_P (insn_b
)
2177 || (set_b
= single_set (insn_b
)) == NULL_RTX
2178 || ! rtx_equal_p (x
, SET_DEST (set_b
))
2179 || reg_overlap_mentioned_p (x
, SET_SRC (set_b
))
2180 || modified_between_p (SET_SRC (set_b
),
2181 PREV_INSN (if_info
.cond_earliest
), jump
)
2182 /* Likewise with X. In particular this can happen when
2183 noce_get_condition looks farther back in the instruction
2184 stream than one might expect. */
2185 || reg_overlap_mentioned_p (x
, cond
)
2186 || reg_overlap_mentioned_p (x
, a
)
2187 || modified_between_p (x
, PREV_INSN (if_info
.cond_earliest
), jump
))
2188 insn_b
= set_b
= NULL_RTX
;
2191 /* If x has side effects then only the if-then-else form is safe to
2192 convert. But even in that case we would need to restore any notes
2193 (such as REG_INC) at then end. That can be tricky if
2194 noce_emit_move_insn expands to more than one insn, so disable the
2195 optimization entirely for now if there are side effects. */
2196 if (side_effects_p (x
))
2199 b
= (set_b
? SET_SRC (set_b
) : x
);
2201 /* Only operate on register destinations, and even then avoid extending
2202 the lifetime of hard registers on small register class machines. */
2205 || (SMALL_REGISTER_CLASSES
2206 && REGNO (x
) < FIRST_PSEUDO_REGISTER
))
2208 if (no_new_pseudos
|| GET_MODE (x
) == BLKmode
)
2210 x
= gen_reg_rtx (GET_MODE (GET_CODE (x
) == STRICT_LOW_PART
2211 ? XEXP (x
, 0) : x
));
2214 /* Don't operate on sources that may trap or are volatile. */
2215 if (! noce_operand_ok (a
) || ! noce_operand_ok (b
))
2218 /* Set up the info block for our subroutines. */
2219 if_info
.test_bb
= test_bb
;
2220 if_info
.cond
= cond
;
2221 if_info
.jump
= jump
;
2222 if_info
.insn_a
= insn_a
;
2223 if_info
.insn_b
= insn_b
;
2227 if_info
.b_unconditional
= else_bb
== 0;
2229 /* Try optimizations in some approximation of a useful order. */
2230 /* ??? Should first look to see if X is live incoming at all. If it
2231 isn't, we don't need anything but an unconditional set. */
2233 /* Look and see if A and B are really the same. Avoid creating silly
2234 cmove constructs that no one will fix up later. */
2235 if (rtx_equal_p (a
, b
))
2237 /* If we have an INSN_B, we don't have to create any new rtl. Just
2238 move the instruction that we already have. If we don't have an
2239 INSN_B, that means that A == X, and we've got a noop move. In
2240 that case don't do anything and let the code below delete INSN_A. */
2241 if (insn_b
&& else_bb
)
2245 if (else_bb
&& insn_b
== BB_END (else_bb
))
2246 BB_END (else_bb
) = PREV_INSN (insn_b
);
2247 reorder_insns (insn_b
, insn_b
, PREV_INSN (jump
));
2249 /* If there was a REG_EQUAL note, delete it since it may have been
2250 true due to this insn being after a jump. */
2251 if ((note
= find_reg_note (insn_b
, REG_EQUAL
, NULL_RTX
)) != 0)
2252 remove_note (insn_b
, note
);
2256 /* If we have "x = b; if (...) x = a;", and x has side-effects, then
2257 x must be executed twice. */
2258 else if (insn_b
&& side_effects_p (orig_x
))
2265 /* Disallow the "if (...) x = a;" form (with an implicit "else x = x;")
2266 for optimizations if writing to x may trap or fault, i.e. it's a memory
2267 other than a static var or a stack slot, is misaligned on strict
2268 aligned machines or is read-only.
2269 If x is a read-only memory, then the program is valid only if we
2270 avoid the store into it. If there are stores on both the THEN and
2271 ELSE arms, then we can go ahead with the conversion; either the
2272 program is broken, or the condition is always false such that the
2273 other memory is selected. */
2274 if (!set_b
&& MEM_P (orig_x
) && noce_mem_write_may_trap_or_fault_p (orig_x
))
2277 if (noce_try_move (&if_info
))
2279 if (noce_try_store_flag (&if_info
))
2281 if (noce_try_bitop (&if_info
))
2283 if (noce_try_minmax (&if_info
))
2285 if (noce_try_abs (&if_info
))
2287 if (HAVE_conditional_move
2288 && noce_try_cmove (&if_info
))
2290 if (! HAVE_conditional_execution
)
2292 if (noce_try_store_flag_constants (&if_info
))
2294 if (noce_try_addcc (&if_info
))
2296 if (noce_try_store_flag_mask (&if_info
))
2298 if (HAVE_conditional_move
2299 && noce_try_cmove_arith (&if_info
))
2301 if (noce_try_sign_mask (&if_info
))
2308 /* The original sets may now be killed. */
2309 delete_insn (insn_a
);
2311 /* Several special cases here: First, we may have reused insn_b above,
2312 in which case insn_b is now NULL. Second, we want to delete insn_b
2313 if it came from the ELSE block, because follows the now correct
2314 write that appears in the TEST block. However, if we got insn_b from
2315 the TEST block, it may in fact be loading data needed for the comparison.
2316 We'll let life_analysis remove the insn if it's really dead. */
2317 if (insn_b
&& else_bb
)
2318 delete_insn (insn_b
);
2320 /* The new insns will have been inserted immediately before the jump. We
2321 should be able to remove the jump with impunity, but the condition itself
2322 may have been modified by gcse to be shared across basic blocks. */
2325 /* If we used a temporary, fix it up now. */
2329 noce_emit_move_insn (orig_x
, x
);
2330 insn_b
= get_insns ();
2331 set_used_flags (orig_x
);
2332 unshare_all_rtl_in_chain (insn_b
);
2335 emit_insn_after_setloc (insn_b
, BB_END (test_bb
), INSN_LOCATOR (insn_a
));
2338 /* Merge the blocks! */
2339 merge_if_block (ce_info
);
2344 /* Attempt to convert an IF-THEN or IF-THEN-ELSE block into
2345 straight line code. Return true if successful. */
2348 process_if_block (struct ce_if_block
* ce_info
)
2350 if (! reload_completed
2351 && noce_process_if_block (ce_info
))
2354 if (HAVE_conditional_execution
&& reload_completed
)
2356 /* If we have && and || tests, try to first handle combining the && and
2357 || tests into the conditional code, and if that fails, go back and
2358 handle it without the && and ||, which at present handles the && case
2359 if there was no ELSE block. */
2360 if (cond_exec_process_if_block (ce_info
, TRUE
))
2363 if (ce_info
->num_multiple_test_blocks
)
2367 if (cond_exec_process_if_block (ce_info
, FALSE
))
2375 /* Merge the blocks and mark for local life update. */
2378 merge_if_block (struct ce_if_block
* ce_info
)
2380 basic_block test_bb
= ce_info
->test_bb
; /* last test block */
2381 basic_block then_bb
= ce_info
->then_bb
; /* THEN */
2382 basic_block else_bb
= ce_info
->else_bb
; /* ELSE or NULL */
2383 basic_block join_bb
= ce_info
->join_bb
; /* join block */
2384 basic_block combo_bb
;
2386 /* All block merging is done into the lower block numbers. */
2390 /* Merge any basic blocks to handle && and || subtests. Each of
2391 the blocks are on the fallthru path from the predecessor block. */
2392 if (ce_info
->num_multiple_test_blocks
> 0)
2394 basic_block bb
= test_bb
;
2395 basic_block last_test_bb
= ce_info
->last_test_bb
;
2396 basic_block fallthru
= block_fallthru (bb
);
2401 fallthru
= block_fallthru (bb
);
2402 merge_blocks (combo_bb
, bb
);
2405 while (bb
!= last_test_bb
);
2408 /* Merge TEST block into THEN block. Normally the THEN block won't have a
2409 label, but it might if there were || tests. That label's count should be
2410 zero, and it normally should be removed. */
2414 if (combo_bb
->il
.rtl
->global_live_at_end
)
2415 COPY_REG_SET (combo_bb
->il
.rtl
->global_live_at_end
,
2416 then_bb
->il
.rtl
->global_live_at_end
);
2417 merge_blocks (combo_bb
, then_bb
);
2421 /* The ELSE block, if it existed, had a label. That label count
2422 will almost always be zero, but odd things can happen when labels
2423 get their addresses taken. */
2426 merge_blocks (combo_bb
, else_bb
);
2430 /* If there was no join block reported, that means it was not adjacent
2431 to the others, and so we cannot merge them. */
2435 rtx last
= BB_END (combo_bb
);
2437 /* The outgoing edge for the current COMBO block should already
2438 be correct. Verify this. */
2439 if (EDGE_COUNT (combo_bb
->succs
) == 0)
2440 gcc_assert (find_reg_note (last
, REG_NORETURN
, NULL
)
2441 || (NONJUMP_INSN_P (last
)
2442 && GET_CODE (PATTERN (last
)) == TRAP_IF
2443 && (TRAP_CONDITION (PATTERN (last
))
2444 == const_true_rtx
)));
2447 /* There should still be something at the end of the THEN or ELSE
2448 blocks taking us to our final destination. */
2449 gcc_assert (JUMP_P (last
)
2450 || (EDGE_SUCC (combo_bb
, 0)->dest
== EXIT_BLOCK_PTR
2452 && SIBLING_CALL_P (last
))
2453 || ((EDGE_SUCC (combo_bb
, 0)->flags
& EDGE_EH
)
2454 && can_throw_internal (last
)));
2457 /* The JOIN block may have had quite a number of other predecessors too.
2458 Since we've already merged the TEST, THEN and ELSE blocks, we should
2459 have only one remaining edge from our if-then-else diamond. If there
2460 is more than one remaining edge, it must come from elsewhere. There
2461 may be zero incoming edges if the THEN block didn't actually join
2462 back up (as with a call to a non-return function). */
2463 else if (EDGE_COUNT (join_bb
->preds
) < 2
2464 && join_bb
!= EXIT_BLOCK_PTR
)
2466 /* We can merge the JOIN. */
2467 if (combo_bb
->il
.rtl
->global_live_at_end
)
2468 COPY_REG_SET (combo_bb
->il
.rtl
->global_live_at_end
,
2469 join_bb
->il
.rtl
->global_live_at_end
);
2471 merge_blocks (combo_bb
, join_bb
);
2476 /* We cannot merge the JOIN. */
2478 /* The outgoing edge for the current COMBO block should already
2479 be correct. Verify this. */
2480 gcc_assert (single_succ_p (combo_bb
)
2481 && single_succ (combo_bb
) == join_bb
);
2483 /* Remove the jump and cruft from the end of the COMBO block. */
2484 if (join_bb
!= EXIT_BLOCK_PTR
)
2485 tidy_fallthru_edge (single_succ_edge (combo_bb
));
2488 num_updated_if_blocks
++;
2491 /* Find a block ending in a simple IF condition and try to transform it
2492 in some way. When converting a multi-block condition, put the new code
2493 in the first such block and delete the rest. Return a pointer to this
2494 first block if some transformation was done. Return NULL otherwise. */
2497 find_if_header (basic_block test_bb
, int pass
)
2499 ce_if_block_t ce_info
;
2503 /* The kind of block we're looking for has exactly two successors. */
2504 if (EDGE_COUNT (test_bb
->succs
) != 2)
2507 then_edge
= EDGE_SUCC (test_bb
, 0);
2508 else_edge
= EDGE_SUCC (test_bb
, 1);
2510 /* Neither edge should be abnormal. */
2511 if ((then_edge
->flags
& EDGE_COMPLEX
)
2512 || (else_edge
->flags
& EDGE_COMPLEX
))
2515 /* Nor exit the loop. */
2516 if ((then_edge
->flags
& EDGE_LOOP_EXIT
)
2517 || (else_edge
->flags
& EDGE_LOOP_EXIT
))
2520 /* The THEN edge is canonically the one that falls through. */
2521 if (then_edge
->flags
& EDGE_FALLTHRU
)
2523 else if (else_edge
->flags
& EDGE_FALLTHRU
)
2526 else_edge
= then_edge
;
2530 /* Otherwise this must be a multiway branch of some sort. */
2533 memset (&ce_info
, '\0', sizeof (ce_info
));
2534 ce_info
.test_bb
= test_bb
;
2535 ce_info
.then_bb
= then_edge
->dest
;
2536 ce_info
.else_bb
= else_edge
->dest
;
2537 ce_info
.pass
= pass
;
2539 #ifdef IFCVT_INIT_EXTRA_FIELDS
2540 IFCVT_INIT_EXTRA_FIELDS (&ce_info
);
2543 if (find_if_block (&ce_info
))
2546 if (HAVE_trap
&& HAVE_conditional_trap
2547 && find_cond_trap (test_bb
, then_edge
, else_edge
))
2550 if (dom_computed
[CDI_POST_DOMINATORS
] >= DOM_NO_FAST_QUERY
2551 && (! HAVE_conditional_execution
|| reload_completed
))
2553 if (find_if_case_1 (test_bb
, then_edge
, else_edge
))
2555 if (find_if_case_2 (test_bb
, then_edge
, else_edge
))
2563 fprintf (dump_file
, "Conversion succeeded on pass %d.\n", pass
);
2564 return ce_info
.test_bb
;
2567 /* Return true if a block has two edges, one of which falls through to the next
2568 block, and the other jumps to a specific block, so that we can tell if the
2569 block is part of an && test or an || test. Returns either -1 or the number
2570 of non-note, non-jump, non-USE/CLOBBER insns in the block. */
2573 block_jumps_and_fallthru_p (basic_block cur_bb
, basic_block target_bb
)
2576 int fallthru_p
= FALSE
;
2583 if (!cur_bb
|| !target_bb
)
2586 /* If no edges, obviously it doesn't jump or fallthru. */
2587 if (EDGE_COUNT (cur_bb
->succs
) == 0)
2590 FOR_EACH_EDGE (cur_edge
, ei
, cur_bb
->succs
)
2592 if (cur_edge
->flags
& EDGE_COMPLEX
)
2593 /* Anything complex isn't what we want. */
2596 else if (cur_edge
->flags
& EDGE_FALLTHRU
)
2599 else if (cur_edge
->dest
== target_bb
)
2606 if ((jump_p
& fallthru_p
) == 0)
2609 /* Don't allow calls in the block, since this is used to group && and ||
2610 together for conditional execution support. ??? we should support
2611 conditional execution support across calls for IA-64 some day, but
2612 for now it makes the code simpler. */
2613 end
= BB_END (cur_bb
);
2614 insn
= BB_HEAD (cur_bb
);
2616 while (insn
!= NULL_RTX
)
2623 && GET_CODE (PATTERN (insn
)) != USE
2624 && GET_CODE (PATTERN (insn
)) != CLOBBER
)
2630 insn
= NEXT_INSN (insn
);
2636 /* Determine if a given basic block heads a simple IF-THEN or IF-THEN-ELSE
2637 block. If so, we'll try to convert the insns to not require the branch.
2638 Return TRUE if we were successful at converting the block. */
2641 find_if_block (struct ce_if_block
* ce_info
)
2643 basic_block test_bb
= ce_info
->test_bb
;
2644 basic_block then_bb
= ce_info
->then_bb
;
2645 basic_block else_bb
= ce_info
->else_bb
;
2646 basic_block join_bb
= NULL_BLOCK
;
2651 ce_info
->last_test_bb
= test_bb
;
2653 /* Discover if any fall through predecessors of the current test basic block
2654 were && tests (which jump to the else block) or || tests (which jump to
2656 if (HAVE_conditional_execution
&& reload_completed
2657 && single_pred_p (test_bb
)
2658 && single_pred_edge (test_bb
)->flags
== EDGE_FALLTHRU
)
2660 basic_block bb
= single_pred (test_bb
);
2661 basic_block target_bb
;
2662 int max_insns
= MAX_CONDITIONAL_EXECUTE
;
2665 /* Determine if the preceding block is an && or || block. */
2666 if ((n_insns
= block_jumps_and_fallthru_p (bb
, else_bb
)) >= 0)
2668 ce_info
->and_and_p
= TRUE
;
2669 target_bb
= else_bb
;
2671 else if ((n_insns
= block_jumps_and_fallthru_p (bb
, then_bb
)) >= 0)
2673 ce_info
->and_and_p
= FALSE
;
2674 target_bb
= then_bb
;
2677 target_bb
= NULL_BLOCK
;
2679 if (target_bb
&& n_insns
<= max_insns
)
2681 int total_insns
= 0;
2684 ce_info
->last_test_bb
= test_bb
;
2686 /* Found at least one && or || block, look for more. */
2689 ce_info
->test_bb
= test_bb
= bb
;
2690 total_insns
+= n_insns
;
2693 if (!single_pred_p (bb
))
2696 bb
= single_pred (bb
);
2697 n_insns
= block_jumps_and_fallthru_p (bb
, target_bb
);
2699 while (n_insns
>= 0 && (total_insns
+ n_insns
) <= max_insns
);
2701 ce_info
->num_multiple_test_blocks
= blocks
;
2702 ce_info
->num_multiple_test_insns
= total_insns
;
2704 if (ce_info
->and_and_p
)
2705 ce_info
->num_and_and_blocks
= blocks
;
2707 ce_info
->num_or_or_blocks
= blocks
;
2711 /* The THEN block of an IF-THEN combo must have exactly one predecessor,
2712 other than any || blocks which jump to the THEN block. */
2713 if ((EDGE_COUNT (then_bb
->preds
) - ce_info
->num_or_or_blocks
) != 1)
2716 /* The edges of the THEN and ELSE blocks cannot have complex edges. */
2717 FOR_EACH_EDGE (cur_edge
, ei
, then_bb
->preds
)
2719 if (cur_edge
->flags
& EDGE_COMPLEX
)
2723 FOR_EACH_EDGE (cur_edge
, ei
, else_bb
->preds
)
2725 if (cur_edge
->flags
& EDGE_COMPLEX
)
2729 /* The THEN block of an IF-THEN combo must have zero or one successors. */
2730 if (EDGE_COUNT (then_bb
->succs
) > 0
2731 && (!single_succ_p (then_bb
)
2732 || (single_succ_edge (then_bb
)->flags
& EDGE_COMPLEX
)
2733 || (flow2_completed
&& tablejump_p (BB_END (then_bb
), NULL
, NULL
))))
2736 /* If the THEN block has no successors, conditional execution can still
2737 make a conditional call. Don't do this unless the ELSE block has
2738 only one incoming edge -- the CFG manipulation is too ugly otherwise.
2739 Check for the last insn of the THEN block being an indirect jump, which
2740 is listed as not having any successors, but confuses the rest of the CE
2741 code processing. ??? we should fix this in the future. */
2742 if (EDGE_COUNT (then_bb
->succs
) == 0)
2744 if (single_pred_p (else_bb
))
2746 rtx last_insn
= BB_END (then_bb
);
2749 && NOTE_P (last_insn
)
2750 && last_insn
!= BB_HEAD (then_bb
))
2751 last_insn
= PREV_INSN (last_insn
);
2754 && JUMP_P (last_insn
)
2755 && ! simplejump_p (last_insn
))
2759 else_bb
= NULL_BLOCK
;
2765 /* If the THEN block's successor is the other edge out of the TEST block,
2766 then we have an IF-THEN combo without an ELSE. */
2767 else if (single_succ (then_bb
) == else_bb
)
2770 else_bb
= NULL_BLOCK
;
2773 /* If the THEN and ELSE block meet in a subsequent block, and the ELSE
2774 has exactly one predecessor and one successor, and the outgoing edge
2775 is not complex, then we have an IF-THEN-ELSE combo. */
2776 else if (single_succ_p (else_bb
)
2777 && single_succ (then_bb
) == single_succ (else_bb
)
2778 && single_pred_p (else_bb
)
2779 && ! (single_succ_edge (else_bb
)->flags
& EDGE_COMPLEX
)
2780 && ! (flow2_completed
&& tablejump_p (BB_END (else_bb
), NULL
, NULL
)))
2781 join_bb
= single_succ (else_bb
);
2783 /* Otherwise it is not an IF-THEN or IF-THEN-ELSE combination. */
2787 num_possible_if_blocks
++;
2792 "\nIF-THEN%s block found, pass %d, start block %d "
2793 "[insn %d], then %d [%d]",
2794 (else_bb
) ? "-ELSE" : "",
2797 BB_HEAD (test_bb
) ? (int)INSN_UID (BB_HEAD (test_bb
)) : -1,
2799 BB_HEAD (then_bb
) ? (int)INSN_UID (BB_HEAD (then_bb
)) : -1);
2802 fprintf (dump_file
, ", else %d [%d]",
2804 BB_HEAD (else_bb
) ? (int)INSN_UID (BB_HEAD (else_bb
)) : -1);
2806 fprintf (dump_file
, ", join %d [%d]",
2808 BB_HEAD (join_bb
) ? (int)INSN_UID (BB_HEAD (join_bb
)) : -1);
2810 if (ce_info
->num_multiple_test_blocks
> 0)
2811 fprintf (dump_file
, ", %d %s block%s last test %d [%d]",
2812 ce_info
->num_multiple_test_blocks
,
2813 (ce_info
->and_and_p
) ? "&&" : "||",
2814 (ce_info
->num_multiple_test_blocks
== 1) ? "" : "s",
2815 ce_info
->last_test_bb
->index
,
2816 ((BB_HEAD (ce_info
->last_test_bb
))
2817 ? (int)INSN_UID (BB_HEAD (ce_info
->last_test_bb
))
2820 fputc ('\n', dump_file
);
2823 /* Make sure IF, THEN, and ELSE, blocks are adjacent. Actually, we get the
2824 first condition for free, since we've already asserted that there's a
2825 fallthru edge from IF to THEN. Likewise for the && and || blocks, since
2826 we checked the FALLTHRU flag, those are already adjacent to the last IF
2828 /* ??? As an enhancement, move the ELSE block. Have to deal with
2829 BLOCK notes, if by no other means than backing out the merge if they
2830 exist. Sticky enough I don't want to think about it now. */
2832 if (else_bb
&& (next
= next
->next_bb
) != else_bb
)
2834 if ((next
= next
->next_bb
) != join_bb
&& join_bb
!= EXIT_BLOCK_PTR
)
2842 /* Do the real work. */
2843 ce_info
->else_bb
= else_bb
;
2844 ce_info
->join_bb
= join_bb
;
2846 return process_if_block (ce_info
);
2849 /* Convert a branch over a trap, or a branch
2850 to a trap, into a conditional trap. */
2853 find_cond_trap (basic_block test_bb
, edge then_edge
, edge else_edge
)
2855 basic_block then_bb
= then_edge
->dest
;
2856 basic_block else_bb
= else_edge
->dest
;
2857 basic_block other_bb
, trap_bb
;
2858 rtx trap
, jump
, cond
, cond_earliest
, seq
;
2861 /* Locate the block with the trap instruction. */
2862 /* ??? While we look for no successors, we really ought to allow
2863 EH successors. Need to fix merge_if_block for that to work. */
2864 if ((trap
= block_has_only_trap (then_bb
)) != NULL
)
2865 trap_bb
= then_bb
, other_bb
= else_bb
;
2866 else if ((trap
= block_has_only_trap (else_bb
)) != NULL
)
2867 trap_bb
= else_bb
, other_bb
= then_bb
;
2873 fprintf (dump_file
, "\nTRAP-IF block found, start %d, trap %d\n",
2874 test_bb
->index
, trap_bb
->index
);
2877 /* If this is not a standard conditional jump, we can't parse it. */
2878 jump
= BB_END (test_bb
);
2879 cond
= noce_get_condition (jump
, &cond_earliest
);
2883 /* If the conditional jump is more than just a conditional jump, then
2884 we can not do if-conversion on this block. */
2885 if (! onlyjump_p (jump
))
2888 /* We must be comparing objects whose modes imply the size. */
2889 if (GET_MODE (XEXP (cond
, 0)) == BLKmode
)
2892 /* Reverse the comparison code, if necessary. */
2893 code
= GET_CODE (cond
);
2894 if (then_bb
== trap_bb
)
2896 code
= reversed_comparison_code (cond
, jump
);
2897 if (code
== UNKNOWN
)
2901 /* Attempt to generate the conditional trap. */
2902 seq
= gen_cond_trap (code
, XEXP (cond
, 0),
2904 TRAP_CODE (PATTERN (trap
)));
2910 /* Emit the new insns before cond_earliest. */
2911 emit_insn_before_setloc (seq
, cond_earliest
, INSN_LOCATOR (trap
));
2913 /* Delete the trap block if possible. */
2914 remove_edge (trap_bb
== then_bb
? then_edge
: else_edge
);
2915 if (EDGE_COUNT (trap_bb
->preds
) == 0)
2916 delete_basic_block (trap_bb
);
2918 /* If the non-trap block and the test are now adjacent, merge them.
2919 Otherwise we must insert a direct branch. */
2920 if (test_bb
->next_bb
== other_bb
)
2922 struct ce_if_block new_ce_info
;
2924 memset (&new_ce_info
, '\0', sizeof (new_ce_info
));
2925 new_ce_info
.test_bb
= test_bb
;
2926 new_ce_info
.then_bb
= NULL
;
2927 new_ce_info
.else_bb
= NULL
;
2928 new_ce_info
.join_bb
= other_bb
;
2929 merge_if_block (&new_ce_info
);
2935 lab
= JUMP_LABEL (jump
);
2936 newjump
= emit_jump_insn_after (gen_jump (lab
), jump
);
2937 LABEL_NUSES (lab
) += 1;
2938 JUMP_LABEL (newjump
) = lab
;
2939 emit_barrier_after (newjump
);
2947 /* Subroutine of find_cond_trap: if BB contains only a trap insn,
2951 block_has_only_trap (basic_block bb
)
2955 /* We're not the exit block. */
2956 if (bb
== EXIT_BLOCK_PTR
)
2959 /* The block must have no successors. */
2960 if (EDGE_COUNT (bb
->succs
) > 0)
2963 /* The only instruction in the THEN block must be the trap. */
2964 trap
= first_active_insn (bb
);
2965 if (! (trap
== BB_END (bb
)
2966 && GET_CODE (PATTERN (trap
)) == TRAP_IF
2967 && TRAP_CONDITION (PATTERN (trap
)) == const_true_rtx
))
2973 /* Look for IF-THEN-ELSE cases in which one of THEN or ELSE is
2974 transformable, but not necessarily the other. There need be no
2977 Return TRUE if we were successful at converting the block.
2979 Cases we'd like to look at:
2982 if (test) goto over; // x not live
2990 if (! test) goto label;
2993 if (test) goto E; // x not live
3007 (3) // This one's really only interesting for targets that can do
3008 // multiway branching, e.g. IA-64 BBB bundles. For other targets
3009 // it results in multiple branches on a cache line, which often
3010 // does not sit well with predictors.
3012 if (test1) goto E; // predicted not taken
3028 (A) Don't do (2) if the branch is predicted against the block we're
3029 eliminating. Do it anyway if we can eliminate a branch; this requires
3030 that the sole successor of the eliminated block postdominate the other
3033 (B) With CE, on (3) we can steal from both sides of the if, creating
3042 Again, this is most useful if J postdominates.
3044 (C) CE substitutes for helpful life information.
3046 (D) These heuristics need a lot of work. */
3048 /* Tests for case 1 above. */
3051 find_if_case_1 (basic_block test_bb
, edge then_edge
, edge else_edge
)
3053 basic_block then_bb
= then_edge
->dest
;
3054 basic_block else_bb
= else_edge
->dest
, new_bb
;
3057 /* If we are partitioning hot/cold basic blocks, we don't want to
3058 mess up unconditional or indirect jumps that cross between hot
3061 Basic block partitioning may result in some jumps that appear to
3062 be optimizable (or blocks that appear to be mergeable), but which really
3063 must be left untouched (they are required to make it safely across
3064 partition boundaries). See the comments at the top of
3065 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
3067 if ((BB_END (then_bb
)
3068 && find_reg_note (BB_END (then_bb
), REG_CROSSING_JUMP
, NULL_RTX
))
3069 || (BB_END (test_bb
)
3070 && find_reg_note (BB_END (test_bb
), REG_CROSSING_JUMP
, NULL_RTX
))
3071 || (BB_END (else_bb
)
3072 && find_reg_note (BB_END (else_bb
), REG_CROSSING_JUMP
,
3076 /* THEN has one successor. */
3077 if (!single_succ_p (then_bb
))
3080 /* THEN does not fall through, but is not strange either. */
3081 if (single_succ_edge (then_bb
)->flags
& (EDGE_COMPLEX
| EDGE_FALLTHRU
))
3084 /* THEN has one predecessor. */
3085 if (!single_pred_p (then_bb
))
3088 /* THEN must do something. */
3089 if (forwarder_block_p (then_bb
))
3092 num_possible_if_blocks
++;
3095 "\nIF-CASE-1 found, start %d, then %d\n",
3096 test_bb
->index
, then_bb
->index
);
3098 /* THEN is small. */
3099 if (! cheap_bb_rtx_cost_p (then_bb
, COSTS_N_INSNS (BRANCH_COST
)))
3102 /* Registers set are dead, or are predicable. */
3103 if (! dead_or_predicable (test_bb
, then_bb
, else_bb
,
3104 single_succ (then_bb
), 1))
3107 /* Conversion went ok, including moving the insns and fixing up the
3108 jump. Adjust the CFG to match. */
3110 bitmap_ior (test_bb
->il
.rtl
->global_live_at_end
,
3111 else_bb
->il
.rtl
->global_live_at_start
,
3112 then_bb
->il
.rtl
->global_live_at_end
);
3115 /* We can avoid creating a new basic block if then_bb is immediately
3116 followed by else_bb, i.e. deleting then_bb allows test_bb to fall
3119 if (then_bb
->next_bb
== else_bb
3120 && then_bb
->prev_bb
== test_bb
3121 && else_bb
!= EXIT_BLOCK_PTR
)
3123 redirect_edge_succ (FALLTHRU_EDGE (test_bb
), else_bb
);
3127 new_bb
= redirect_edge_and_branch_force (FALLTHRU_EDGE (test_bb
),
3130 then_bb_index
= then_bb
->index
;
3131 delete_basic_block (then_bb
);
3133 /* Make rest of code believe that the newly created block is the THEN_BB
3134 block we removed. */
3137 new_bb
->index
= then_bb_index
;
3138 SET_BASIC_BLOCK (then_bb_index
, new_bb
);
3139 /* Since the fallthru edge was redirected from test_bb to new_bb,
3140 we need to ensure that new_bb is in the same partition as
3141 test bb (you can not fall through across section boundaries). */
3142 BB_COPY_PARTITION (new_bb
, test_bb
);
3144 /* We've possibly created jump to next insn, cleanup_cfg will solve that
3148 num_updated_if_blocks
++;
3153 /* Test for case 2 above. */
3156 find_if_case_2 (basic_block test_bb
, edge then_edge
, edge else_edge
)
3158 basic_block then_bb
= then_edge
->dest
;
3159 basic_block else_bb
= else_edge
->dest
;
3163 /* If we are partitioning hot/cold basic blocks, we don't want to
3164 mess up unconditional or indirect jumps that cross between hot
3167 Basic block partitioning may result in some jumps that appear to
3168 be optimizable (or blocks that appear to be mergeable), but which really
3169 must be left untouched (they are required to make it safely across
3170 partition boundaries). See the comments at the top of
3171 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
3173 if ((BB_END (then_bb
)
3174 && find_reg_note (BB_END (then_bb
), REG_CROSSING_JUMP
, NULL_RTX
))
3175 || (BB_END (test_bb
)
3176 && find_reg_note (BB_END (test_bb
), REG_CROSSING_JUMP
, NULL_RTX
))
3177 || (BB_END (else_bb
)
3178 && find_reg_note (BB_END (else_bb
), REG_CROSSING_JUMP
,
3182 /* ELSE has one successor. */
3183 if (!single_succ_p (else_bb
))
3186 else_succ
= single_succ_edge (else_bb
);
3188 /* ELSE outgoing edge is not complex. */
3189 if (else_succ
->flags
& EDGE_COMPLEX
)
3192 /* ELSE has one predecessor. */
3193 if (!single_pred_p (else_bb
))
3196 /* THEN is not EXIT. */
3197 if (then_bb
->index
< NUM_FIXED_BLOCKS
)
3200 /* ELSE is predicted or SUCC(ELSE) postdominates THEN. */
3201 note
= find_reg_note (BB_END (test_bb
), REG_BR_PROB
, NULL_RTX
);
3202 if (note
&& INTVAL (XEXP (note
, 0)) >= REG_BR_PROB_BASE
/ 2)
3204 else if (else_succ
->dest
->index
< NUM_FIXED_BLOCKS
3205 || dominated_by_p (CDI_POST_DOMINATORS
, then_bb
,
3211 num_possible_if_blocks
++;
3214 "\nIF-CASE-2 found, start %d, else %d\n",
3215 test_bb
->index
, else_bb
->index
);
3217 /* ELSE is small. */
3218 if (! cheap_bb_rtx_cost_p (else_bb
, COSTS_N_INSNS (BRANCH_COST
)))
3221 /* Registers set are dead, or are predicable. */
3222 if (! dead_or_predicable (test_bb
, else_bb
, then_bb
, else_succ
->dest
, 0))
3225 /* Conversion went ok, including moving the insns and fixing up the
3226 jump. Adjust the CFG to match. */
3228 bitmap_ior (test_bb
->il
.rtl
->global_live_at_end
,
3229 then_bb
->il
.rtl
->global_live_at_start
,
3230 else_bb
->il
.rtl
->global_live_at_end
);
3232 delete_basic_block (else_bb
);
3235 num_updated_if_blocks
++;
3237 /* ??? We may now fallthru from one of THEN's successors into a join
3238 block. Rerun cleanup_cfg? Examine things manually? Wait? */
3243 /* A subroutine of dead_or_predicable called through for_each_rtx.
3244 Return 1 if a memory is found. */
3247 find_memory (rtx
*px
, void *data ATTRIBUTE_UNUSED
)
3252 /* Used by the code above to perform the actual rtl transformations.
3253 Return TRUE if successful.
3255 TEST_BB is the block containing the conditional branch. MERGE_BB
3256 is the block containing the code to manipulate. NEW_DEST is the
3257 label TEST_BB should be branching to after the conversion.
3258 REVERSEP is true if the sense of the branch should be reversed. */
3261 dead_or_predicable (basic_block test_bb
, basic_block merge_bb
,
3262 basic_block other_bb
, basic_block new_dest
, int reversep
)
3264 rtx head
, end
, jump
, earliest
= NULL_RTX
, old_dest
, new_label
= NULL_RTX
;
3266 jump
= BB_END (test_bb
);
3268 /* Find the extent of the real code in the merge block. */
3269 head
= BB_HEAD (merge_bb
);
3270 end
= BB_END (merge_bb
);
3273 head
= NEXT_INSN (head
);
3278 head
= end
= NULL_RTX
;
3281 head
= NEXT_INSN (head
);
3288 head
= end
= NULL_RTX
;
3291 end
= PREV_INSN (end
);
3294 /* Disable handling dead code by conditional execution if the machine needs
3295 to do anything funny with the tests, etc. */
3296 #ifndef IFCVT_MODIFY_TESTS
3297 if (HAVE_conditional_execution
)
3299 /* In the conditional execution case, we have things easy. We know
3300 the condition is reversible. We don't have to check life info
3301 because we're going to conditionally execute the code anyway.
3302 All that's left is making sure the insns involved can actually
3307 cond
= cond_exec_get_condition (jump
);
3311 prob_val
= find_reg_note (jump
, REG_BR_PROB
, NULL_RTX
);
3313 prob_val
= XEXP (prob_val
, 0);
3317 enum rtx_code rev
= reversed_comparison_code (cond
, jump
);
3320 cond
= gen_rtx_fmt_ee (rev
, GET_MODE (cond
), XEXP (cond
, 0),
3323 prob_val
= GEN_INT (REG_BR_PROB_BASE
- INTVAL (prob_val
));
3326 if (! cond_exec_process_insns ((ce_if_block_t
*)0, head
, end
, cond
,
3335 /* In the non-conditional execution case, we have to verify that there
3336 are no trapping operations, no calls, no references to memory, and
3337 that any registers modified are dead at the branch site. */
3339 rtx insn
, cond
, prev
;
3340 regset merge_set
, tmp
, test_live
, test_set
;
3341 struct propagate_block_info
*pbi
;
3342 unsigned i
, fail
= 0;
3345 /* Check for no calls or trapping operations. */
3346 for (insn
= head
; ; insn
= NEXT_INSN (insn
))
3352 if (may_trap_p (PATTERN (insn
)))
3355 /* ??? Even non-trapping memories such as stack frame
3356 references must be avoided. For stores, we collect
3357 no lifetime info; for reads, we'd have to assert
3358 true_dependence false against every store in the
3360 if (for_each_rtx (&PATTERN (insn
), find_memory
, NULL
))
3367 if (! any_condjump_p (jump
))
3370 /* Find the extent of the conditional. */
3371 cond
= noce_get_condition (jump
, &earliest
);
3376 MERGE_SET = set of registers set in MERGE_BB
3377 TEST_LIVE = set of registers live at EARLIEST
3378 TEST_SET = set of registers set between EARLIEST and the
3379 end of the block. */
3381 tmp
= ALLOC_REG_SET (®_obstack
);
3382 merge_set
= ALLOC_REG_SET (®_obstack
);
3383 test_live
= ALLOC_REG_SET (®_obstack
);
3384 test_set
= ALLOC_REG_SET (®_obstack
);
3386 /* ??? bb->local_set is only valid during calculate_global_regs_live,
3387 so we must recompute usage for MERGE_BB. Not so bad, I suppose,
3388 since we've already asserted that MERGE_BB is small. */
3389 /* If we allocated new pseudos (e.g. in the conditional move
3390 expander called from noce_emit_cmove), we must resize the
3392 if (max_regno
< max_reg_num ())
3394 max_regno
= max_reg_num ();
3395 allocate_reg_info (max_regno
, FALSE
, FALSE
);
3397 propagate_block (merge_bb
, tmp
, merge_set
, merge_set
, 0);
3399 /* For small register class machines, don't lengthen lifetimes of
3400 hard registers before reload. */
3401 if (SMALL_REGISTER_CLASSES
&& ! reload_completed
)
3403 EXECUTE_IF_SET_IN_BITMAP (merge_set
, 0, i
, bi
)
3405 if (i
< FIRST_PSEUDO_REGISTER
3407 && ! global_regs
[i
])
3412 /* For TEST, we're interested in a range of insns, not a whole block.
3413 Moreover, we're interested in the insns live from OTHER_BB. */
3415 COPY_REG_SET (test_live
, other_bb
->il
.rtl
->global_live_at_start
);
3416 pbi
= init_propagate_block_info (test_bb
, test_live
, test_set
, test_set
,
3419 for (insn
= jump
; ; insn
= prev
)
3421 prev
= propagate_one_insn (pbi
, insn
);
3422 if (insn
== earliest
)
3426 free_propagate_block_info (pbi
);
3428 /* We can perform the transformation if
3429 MERGE_SET & (TEST_SET | TEST_LIVE)
3431 TEST_SET & merge_bb->il.rtl->global_live_at_start
3434 if (bitmap_intersect_p (test_set
, merge_set
)
3435 || bitmap_intersect_p (test_live
, merge_set
)
3436 || bitmap_intersect_p (test_set
,
3437 merge_bb
->il
.rtl
->global_live_at_start
))
3441 FREE_REG_SET (merge_set
);
3442 FREE_REG_SET (test_live
);
3443 FREE_REG_SET (test_set
);
3450 /* We don't want to use normal invert_jump or redirect_jump because
3451 we don't want to delete_insn called. Also, we want to do our own
3452 change group management. */
3454 old_dest
= JUMP_LABEL (jump
);
3455 if (other_bb
!= new_dest
)
3457 new_label
= block_label (new_dest
);
3459 ? ! invert_jump_1 (jump
, new_label
)
3460 : ! redirect_jump_1 (jump
, new_label
))
3464 if (! apply_change_group ())
3467 if (other_bb
!= new_dest
)
3469 redirect_jump_2 (jump
, old_dest
, new_label
, -1, reversep
);
3471 redirect_edge_succ (BRANCH_EDGE (test_bb
), new_dest
);
3474 gcov_type count
, probability
;
3475 count
= BRANCH_EDGE (test_bb
)->count
;
3476 BRANCH_EDGE (test_bb
)->count
= FALLTHRU_EDGE (test_bb
)->count
;
3477 FALLTHRU_EDGE (test_bb
)->count
= count
;
3478 probability
= BRANCH_EDGE (test_bb
)->probability
;
3479 BRANCH_EDGE (test_bb
)->probability
3480 = FALLTHRU_EDGE (test_bb
)->probability
;
3481 FALLTHRU_EDGE (test_bb
)->probability
= probability
;
3482 update_br_prob_note (test_bb
);
3486 /* Move the insns out of MERGE_BB to before the branch. */
3491 if (end
== BB_END (merge_bb
))
3492 BB_END (merge_bb
) = PREV_INSN (head
);
3494 if (squeeze_notes (&head
, &end
))
3497 /* PR 21767: When moving insns above a conditional branch, REG_EQUAL
3498 notes might become invalid. */
3504 if (! INSN_P (insn
))
3506 note
= find_reg_note (insn
, REG_EQUAL
, NULL_RTX
);
3509 set
= single_set (insn
);
3510 if (!set
|| !function_invariant_p (SET_SRC (set
)))
3511 remove_note (insn
, note
);
3512 } while (insn
!= end
&& (insn
= NEXT_INSN (insn
)));
3514 reorder_insns (head
, end
, PREV_INSN (earliest
));
3517 /* Remove the jump and edge if we can. */
3518 if (other_bb
== new_dest
)
3521 remove_edge (BRANCH_EDGE (test_bb
));
3522 /* ??? Can't merge blocks here, as then_bb is still in use.
3523 At minimum, the merge will get done just before bb-reorder. */
3533 /* Main entry point for all if-conversion. */
3536 if_convert (int x_life_data_ok
)
3541 num_possible_if_blocks
= 0;
3542 num_updated_if_blocks
= 0;
3543 num_true_changes
= 0;
3544 life_data_ok
= (x_life_data_ok
!= 0);
3546 if ((! targetm
.cannot_modify_jumps_p ())
3547 && (!flag_reorder_blocks_and_partition
|| !no_new_pseudos
3548 || !targetm
.have_named_sections
))
3552 flow_loops_find (&loops
);
3553 mark_loop_exit_edges (&loops
);
3554 flow_loops_free (&loops
);
3555 free_dominance_info (CDI_DOMINATORS
);
3558 /* Compute postdominators if we think we'll use them. */
3559 if (HAVE_conditional_execution
|| life_data_ok
)
3560 calculate_dominance_info (CDI_POST_DOMINATORS
);
3565 /* Go through each of the basic blocks looking for things to convert. If we
3566 have conditional execution, we make multiple passes to allow us to handle
3567 IF-THEN{-ELSE} blocks within other IF-THEN{-ELSE} blocks. */
3571 cond_exec_changed_p
= FALSE
;
3574 #ifdef IFCVT_MULTIPLE_DUMPS
3575 if (dump_file
&& pass
> 1)
3576 fprintf (dump_file
, "\n\n========== Pass %d ==========\n", pass
);
3582 while ((new_bb
= find_if_header (bb
, pass
)))
3586 #ifdef IFCVT_MULTIPLE_DUMPS
3587 if (dump_file
&& cond_exec_changed_p
)
3588 print_rtl_with_bb (dump_file
, get_insns ());
3591 while (cond_exec_changed_p
);
3593 #ifdef IFCVT_MULTIPLE_DUMPS
3595 fprintf (dump_file
, "\n\n========== no more changes\n");
3598 free_dominance_info (CDI_POST_DOMINATORS
);
3603 clear_aux_for_blocks ();
3605 /* Rebuild life info for basic blocks that require it. */
3606 if (num_true_changes
&& life_data_ok
)
3608 /* If we allocated new pseudos, we must resize the array for sched1. */
3609 if (max_regno
< max_reg_num ())
3611 max_regno
= max_reg_num ();
3612 allocate_reg_info (max_regno
, FALSE
, FALSE
);
3614 update_life_info_in_dirty_blocks (UPDATE_LIFE_GLOBAL_RM_NOTES
,
3615 PROP_DEATH_NOTES
| PROP_SCAN_DEAD_CODE
3616 | PROP_KILL_DEAD_CODE
);
3619 /* Write the final stats. */
3620 if (dump_file
&& num_possible_if_blocks
> 0)
3623 "\n%d possible IF blocks searched.\n",
3624 num_possible_if_blocks
);
3626 "%d IF blocks converted.\n",
3627 num_updated_if_blocks
);
3629 "%d true changes made.\n\n\n",
3633 #ifdef ENABLE_CHECKING
3634 verify_flow_info ();
3639 gate_handle_if_conversion (void)
3641 return (optimize
> 0);
3644 /* If-conversion and CFG cleanup. */
3646 rest_of_handle_if_conversion (void)
3648 if (flag_if_conversion
)
3651 dump_flow_info (dump_file
);
3652 cleanup_cfg (CLEANUP_EXPENSIVE
);
3653 reg_scan (get_insns (), max_reg_num ());
3657 timevar_push (TV_JUMP
);
3658 cleanup_cfg (CLEANUP_EXPENSIVE
);
3659 reg_scan (get_insns (), max_reg_num ());
3660 timevar_pop (TV_JUMP
);
3663 struct tree_opt_pass pass_rtl_ifcvt
=
3666 gate_handle_if_conversion
, /* gate */
3667 rest_of_handle_if_conversion
, /* execute */
3670 0, /* static_pass_number */
3671 TV_IFCVT
, /* tv_id */
3672 0, /* properties_required */
3673 0, /* properties_provided */
3674 0, /* properties_destroyed */
3675 0, /* todo_flags_start */
3676 TODO_dump_func
, /* todo_flags_finish */
3681 gate_handle_if_after_combine (void)
3683 return (optimize
> 0 && flag_if_conversion
);
3687 /* Rerun if-conversion, as combine may have simplified things enough
3688 to now meet sequence length restrictions. */
3690 rest_of_handle_if_after_combine (void)
3697 struct tree_opt_pass pass_if_after_combine
=
3700 gate_handle_if_after_combine
, /* gate */
3701 rest_of_handle_if_after_combine
, /* execute */
3704 0, /* static_pass_number */
3705 TV_IFCVT
, /* tv_id */
3706 0, /* properties_required */
3707 0, /* properties_provided */
3708 0, /* properties_destroyed */
3709 0, /* todo_flags_start */
3711 TODO_ggc_collect
, /* todo_flags_finish */
3717 gate_handle_if_after_reload (void)
3719 return (optimize
> 0);
3723 rest_of_handle_if_after_reload (void)
3725 /* Last attempt to optimize CFG, as scheduling, peepholing and insn
3726 splitting possibly introduced more crossjumping opportunities. */
3727 cleanup_cfg (CLEANUP_EXPENSIVE
3728 | CLEANUP_UPDATE_LIFE
3729 | (flag_crossjumping
? CLEANUP_CROSSJUMP
: 0));
3730 if (flag_if_conversion2
)
3735 struct tree_opt_pass pass_if_after_reload
=
3738 gate_handle_if_after_reload
, /* gate */
3739 rest_of_handle_if_after_reload
, /* execute */
3742 0, /* static_pass_number */
3743 TV_IFCVT2
, /* tv_id */
3744 0, /* properties_required */
3745 0, /* properties_provided */
3746 0, /* properties_destroyed */
3747 0, /* todo_flags_start */
3749 TODO_ggc_collect
, /* todo_flags_finish */